SELECT 
  cscart_product_feature_variant_descriptions.variant, 
  cscart_product_feature_variants.variant_id, 
  cscart_product_feature_variants.feature_id, 
  cscart_product_features_values.variant_id as selected, 
  cscart_product_features.feature_type, 
  cscart_seo_names.name as seo_name, 
  cscart_seo_names.path as seo_path, 
  cscart_product_feature_variants.color, 
  cscart_product_features_values.value_int, 
  cscart_product_feature_variants.abt__ut2_multicolor, 
  cscart_product_feature_variants.abt__ut2_color_style 
FROM 
  cscart_product_feature_variants 
  LEFT JOIN cscart_product_feature_variant_descriptions ON cscart_product_feature_variant_descriptions.variant_id = cscart_product_feature_variants.variant_id 
  AND cscart_product_feature_variant_descriptions.lang_code = 'ru' 
  INNER JOIN cscart_product_features_values ON cscart_product_features_values.variant_id = cscart_product_feature_variants.variant_id 
  AND cscart_product_features_values.lang_code = 'ru' 
  AND cscart_product_features_values.product_id = 100 
  AND cscart_product_features_values.feature_id = cscart_product_feature_variants.feature_id 
  LEFT JOIN cscart_product_features ON cscart_product_features.feature_id = cscart_product_feature_variants.feature_id 
  LEFT JOIN cscart_seo_names ON cscart_seo_names.object_id = cscart_product_feature_variants.variant_id 
  AND cscart_seo_names.type = 'e' 
  AND cscart_seo_names.dispatch = '' 
  AND cscart_seo_names.lang_code = 'ru' 
  AND (
    cscart_seo_names.company_id = 1 
    OR cscart_seo_names.company_id = 0
  ) 
WHERE 
  1 
  AND cscart_product_feature_variants.feature_id IN (
    1, 55, 56, 6, 68, 69, 70, 58, 71, 72, 73, 
    74, 75, 76, 39, 66
  ) 
GROUP BY 
  cscart_product_feature_variants.variant_id 
ORDER BY 
  cscart_product_feature_variants.position, 
  cscart_product_feature_variant_descriptions.variant

Query time 0.00365

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "19.61"
    },
    "ordering_operation": {
      "using_filesort": true,
      "grouping_operation": {
        "using_temporary_table": true,
        "using_filesort": false,
        "nested_loop": [
          {
            "table": {
              "table_name": "cscart_product_features_values",
              "access_type": "ref",
              "possible_keys": [
                "PRIMARY",
                "fl",
                "variant_id",
                "lang_code",
                "product_id",
                "fpl",
                "idx_product_feature_variant_id"
              ],
              "key": "product_id",
              "used_key_parts": [
                "product_id"
              ],
              "key_length": "3",
              "ref": [
                "const"
              ],
              "rows_examined_per_scan": 33,
              "rows_produced_per_join": 6,
              "filtered": "21.08",
              "cost_info": {
                "read_cost": "8.25",
                "eval_cost": "0.70",
                "prefix_cost": "11.55",
                "data_read_per_join": "5K"
              },
              "used_columns": [
                "feature_id",
                "product_id",
                "variant_id",
                "value_int",
                "lang_code"
              ],
              "attached_condition": "((`test_uchur_k`.`cscart_product_features_values`.`feature_id` in (1,55,56,6,68,69,70,58,71,72,73,74,75,76,39,66)) and (`test_uchur_k`.`cscart_product_features_values`.`lang_code` = 'ru'))"
            }
          },
          {
            "table": {
              "table_name": "cscart_product_feature_variants",
              "access_type": "eq_ref",
              "possible_keys": [
                "PRIMARY",
                "feature_id"
              ],
              "key": "PRIMARY",
              "used_key_parts": [
                "variant_id"
              ],
              "key_length": "3",
              "ref": [
                "test_uchur_k.cscart_product_features_values.variant_id"
              ],
              "rows_examined_per_scan": 1,
              "rows_produced_per_join": 2,
              "filtered": "38.53",
              "cost_info": {
                "read_cost": "1.74",
                "eval_cost": "0.27",
                "prefix_cost": "13.99",
                "data_read_per_join": "4K"
              },
              "used_columns": [
                "variant_id",
                "feature_id",
                "color",
                "position",
                "abt__ut2_color_style",
                "abt__ut2_multicolor"
              ],
              "attached_condition": "(`test_uchur_k`.`cscart_product_feature_variants`.`feature_id` = `test_uchur_k`.`cscart_product_features_values`.`feature_id`)"
            }
          },
          {
            "table": {
              "table_name": "cscart_product_features",
              "access_type": "eq_ref",
              "possible_keys": [
                "PRIMARY"
              ],
              "key": "PRIMARY",
              "used_key_parts": [
                "feature_id"
              ],
              "key_length": "3",
              "ref": [
                "test_uchur_k.cscart_product_features_values.feature_id"
              ],
              "rows_examined_per_scan": 1,
              "rows_produced_per_join": 2,
              "filtered": "100.00",
              "cost_info": {
                "read_cost": "0.67",
                "eval_cost": "0.27",
                "prefix_cost": "14.92",
                "data_read_per_join": "5K"
              },
              "used_columns": [
                "feature_id",
                "feature_type"
              ]
            }
          },
          {
            "table": {
              "table_name": "cscart_product_feature_variant_descriptions",
              "access_type": "eq_ref",
              "possible_keys": [
                "PRIMARY"
              ],
              "key": "PRIMARY",
              "used_key_parts": [
                "variant_id",
                "lang_code"
              ],
              "key_length": "9",
              "ref": [
                "test_uchur_k.cscart_product_features_values.variant_id",
                "const"
              ],
              "rows_examined_per_scan": 1,
              "rows_produced_per_join": 2,
              "filtered": "100.00",
              "cost_info": {
                "read_cost": "0.67",
                "eval_cost": "0.27",
                "prefix_cost": "15.86",
                "data_read_per_join": "8K"
              },
              "used_columns": [
                "variant_id",
                "variant",
                "lang_code"
              ]
            }
          },
          {
            "table": {
              "table_name": "cscart_seo_names",
              "access_type": "ref",
              "possible_keys": [
                "PRIMARY",
                "dispatch"
              ],
              "key": "PRIMARY",
              "used_key_parts": [
                "object_id",
                "type",
                "dispatch",
                "lang_code"
              ],
              "key_length": "206",
              "ref": [
                "test_uchur_k.cscart_product_features_values.variant_id",
                "const",
                "const",
                "const"
              ],
              "rows_examined_per_scan": 4,
              "rows_produced_per_join": 10,
              "filtered": "100.00",
              "index_condition": "<if>(is_not_null_compl(cscart_seo_names), ((`test_uchur_k`.`cscart_seo_names`.`company_id` = 1) or (`test_uchur_k`.`cscart_seo_names`.`company_id` = 0)), true)",
              "cost_info": {
                "read_cost": "2.68",
                "eval_cost": "1.07",
                "prefix_cost": "19.61",
                "data_read_per_join": "18K"
              },
              "used_columns": [
                "name",
                "object_id",
                "company_id",
                "type",
                "dispatch",
                "path",
                "lang_code"
              ]
            }
          }
        ]
      }
    }
  }
}

Result

variant variant_id feature_id selected feature_type seo_name seo_path color value_int abt__ut2_multicolor abt__ut2_color_style
0.20 мм - 120 м 210 75 210 S #ffffff #ffffff default
4000 209 74 209 S default
5,2:1 181 70 181 S default
52 194 76 194 S default
7 208 73 208 S default
9+1 202 71 202 S default
Series for UCHUR SFU4000 207 55 207 S default
Алюминий 182 58 182 M default
Безынерционные 179 68 179 S default
Демисезон 50 6 50 M default
Карповая 191 69 191 M #ffffff #ffffff default
Китай 147 66 147 S #ffffff #ffffff default
Лето 58 6 58 M #ffffff #ffffff default
Передний 184 72 184 S default
Рыбалка 149 56 149 M default
Серебристый 206 39 206 S #c2c5cc #ffffff thumbnail
МУНХА 178 1 178 E munha-ru #ffffff #ffffff default