SELECT 
  cscart_product_feature_variants.variant_id, 
  cscart_product_feature_variants.position, 
  cscart_product_feature_variants.color, 
  cscart_product_feature_variant_descriptions.variant 
FROM 
  cscart_product_feature_variants 
  LEFT JOIN cscart_product_feature_variant_descriptions ON cscart_product_feature_variants.variant_id = cscart_product_feature_variant_descriptions.variant_id 
  AND cscart_product_feature_variant_descriptions.lang_code = 'ru' 
WHERE 
  cscart_product_feature_variants.variant_id IN (
    1, 15, 50, 58, 237, 162, 265, 282, 504, 
    122, 127, 149, 240, 123, 125, 126, 270, 
    147, 507, 19, 238, 21, 320, 509, 120, 
    121, 146, 262, 508, 234, 287, 18, 20, 
    165, 98, 111, 160, 158, 422, 57, 1300, 
    1826, 1349, 1829, 289, 1813
  ) 
ORDER BY 
  cscart_product_feature_variants.position ASC, 
  cscart_product_feature_variant_descriptions.variant ASC

Query time 0.00096

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "48.31"
    },
    "ordering_operation": {
      "using_temporary_table": true,
      "using_filesort": true,
      "nested_loop": [
        {
          "table": {
            "table_name": "cscart_product_feature_variants",
            "access_type": "range",
            "possible_keys": [
              "PRIMARY"
            ],
            "key": "PRIMARY",
            "used_key_parts": [
              "variant_id"
            ],
            "key_length": "3",
            "rows_examined_per_scan": 46,
            "rows_produced_per_join": 46,
            "filtered": "100.00",
            "index_condition": "(`test_uchur_k`.`cscart_product_feature_variants`.`variant_id` in (1,15,50,58,237,162,265,282,504,122,127,149,240,123,125,126,270,147,507,19,238,21,320,509,120,121,146,262,508,234,287,18,20,165,98,111,160,158,422,57,1300,1826,1349,1829,289,1813))",
            "cost_info": {
              "read_cost": "27.61",
              "eval_cost": "4.60",
              "prefix_cost": "32.21",
              "data_read_per_join": "71K"
            },
            "used_columns": [
              "variant_id",
              "color",
              "position"
            ]
          }
        },
        {
          "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_feature_variants.variant_id",
              "const"
            ],
            "rows_examined_per_scan": 1,
            "rows_produced_per_join": 46,
            "filtered": "100.00",
            "cost_info": {
              "read_cost": "11.50",
              "eval_cost": "4.60",
              "prefix_cost": "48.31",
              "data_read_per_join": "143K"
            },
            "used_columns": [
              "variant_id",
              "variant",
              "lang_code"
            ]
          }
        }
      ]
    }
  }
}