SELECT 
  pfv.feature_id, 
  pfv.product_id, 
  pfv.variant_id, 
  fv.position, 
  fvd.variant 
FROM 
  cscart_product_features_values AS pfv 
  INNER JOIN cscart_product_feature_variants AS fv ON pfv.feature_id = fv.feature_id 
  AND pfv.variant_id = fv.variant_id 
  INNER JOIN cscart_product_feature_variant_descriptions AS fvd ON pfv.variant_id = fvd.variant_id 
  AND fvd.lang_code = 'ru' 
WHERE 
  pfv.feature_id IN (193, 3) 
  AND pfv.product_id IN (
    56, 82, 116, 117, 125, 106, 39, 40, 22710, 
    22711, 17, 57, 122, 58, 5
  ) 
  AND pfv.lang_code = 'ru'

Query time 0.00150

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "18.35"
    },
    "nested_loop": [
      {
        "table": {
          "table_name": "pfv",
          "access_type": "range",
          "possible_keys": [
            "PRIMARY",
            "fl",
            "variant_id",
            "lang_code",
            "product_id",
            "fpl",
            "idx_product_feature_variant_id"
          ],
          "key": "idx_product_feature_variant_id",
          "used_key_parts": [
            "product_id",
            "feature_id",
            "lang_code"
          ],
          "key_length": "12",
          "rows_examined_per_scan": 31,
          "rows_produced_per_join": 31,
          "filtered": "100.00",
          "using_index": true,
          "cost_info": {
            "read_cost": "3.66",
            "eval_cost": "3.10",
            "prefix_cost": "6.76",
            "data_read_per_join": "23K"
          },
          "used_columns": [
            "feature_id",
            "product_id",
            "variant_id",
            "lang_code"
          ],
          "attached_condition": "((`test_uchur_k`.`pfv`.`feature_id` in (193,3)) and (`test_uchur_k`.`pfv`.`product_id` in (56,82,116,117,125,106,39,40,22710,22711,17,57,122,58,5)) and (`test_uchur_k`.`pfv`.`lang_code` = 'ru'))"
        }
      },
      {
        "table": {
          "table_name": "fv",
          "access_type": "eq_ref",
          "possible_keys": [
            "PRIMARY",
            "feature_id"
          ],
          "key": "PRIMARY",
          "used_key_parts": [
            "variant_id"
          ],
          "key_length": "3",
          "ref": [
            "test_uchur_k.pfv.variant_id"
          ],
          "rows_examined_per_scan": 1,
          "rows_produced_per_join": 2,
          "filtered": "6.81",
          "cost_info": {
            "read_cost": "7.75",
            "eval_cost": "0.21",
            "prefix_cost": "17.61",
            "data_read_per_join": "3K"
          },
          "used_columns": [
            "variant_id",
            "feature_id",
            "position"
          ],
          "attached_condition": "(`test_uchur_k`.`fv`.`feature_id` = `test_uchur_k`.`pfv`.`feature_id`)"
        }
      },
      {
        "table": {
          "table_name": "fvd",
          "access_type": "eq_ref",
          "possible_keys": [
            "PRIMARY"
          ],
          "key": "PRIMARY",
          "used_key_parts": [
            "variant_id",
            "lang_code"
          ],
          "key_length": "9",
          "ref": [
            "test_uchur_k.pfv.variant_id",
            "const"
          ],
          "rows_examined_per_scan": 1,
          "rows_produced_per_join": 2,
          "filtered": "100.00",
          "cost_info": {
            "read_cost": "0.53",
            "eval_cost": "0.21",
            "prefix_cost": "18.35",
            "data_read_per_join": "6K"
          },
          "used_columns": [
            "variant_id",
            "variant",
            "lang_code"
          ]
        }
      }
    ]
  }
}

Result

feature_id product_id variant_id position variant
3 5 6 0 OSFA
193 5 1373 0 OSFA
3 17 6 0 OSFA
193 17 1373 0 OSFA
3 39 26 0 размер XL
193 39 1357 0 S
3 40 26 0 размер XL
193 40 1357 0 S
3 56 6 0 OSFA
193 56 1373 0 OSFA
3 57 6 0 OSFA
193 57 1373 0 OSFA
3 58 6 0 OSFA
193 58 1373 0 OSFA
3 82 6 0 OSFA
3 106 6 0 OSFA
193 106 1373 0 OSFA
3 116 39 0 56-60
193 116 1375 0 56-60
3 117 39 0 56-60
193 117 1375 0 56-60
3 122 40 0 62
193 122 1385 0 60
3 125 10 0 M
193 125 1357 0 S
3 22710 26 0 размер XL
193 22710 1358 0 M
3 22711 26 0 размер XL
193 22711 1359 0 L