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 = 'en' 
WHERE 
  pfv.feature_id IN (
    1071, 1199, 347, 345, 1392, 1083, 1086, 
    289, 348, 306
  ) 
  AND pfv.product_id IN (
    26620, 17379, 19139, 19079, 19134, 19151, 
    19294, 26799, 19220, 19069, 18910, 
    16049, 18489, 19187, 19300, 19203, 
    18997, 18896, 17145, 19254, 18825, 
    19105, 19233
  ) 
  AND pfv.lang_code = 'en'

Query time 0.00391

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "27.40"
    },
    "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": "product_id",
          "used_key_parts": [
            "product_id"
          ],
          "key_length": "3",
          "rows_examined_per_scan": 41,
          "rows_produced_per_join": 8,
          "filtered": "21.16",
          "index_condition": "(`cscartdb`.`pfv`.`product_id` in (26620,17379,19139,19079,19134,19151,19294,26799,19220,19069,18910,16049,18489,19187,19300,19203,18997,18896,17145,19254,18825,19105,19233))",
          "cost_info": {
            "read_cost": "23.34",
            "eval_cost": "0.87",
            "prefix_cost": "24.21",
            "data_read_per_join": "6K"
          },
          "used_columns": [
            "feature_id",
            "product_id",
            "variant_id",
            "lang_code"
          ],
          "attached_condition": "((`cscartdb`.`pfv`.`feature_id` in (1071,1199,347,345,1392,1083,1086,289,348,306)) and (`cscartdb`.`pfv`.`lang_code` = 'en'))"
        }
      },
      {
        "table": {
          "table_name": "fv",
          "access_type": "eq_ref",
          "possible_keys": [
            "PRIMARY",
            "feature_id"
          ],
          "key": "PRIMARY",
          "used_key_parts": [
            "variant_id"
          ],
          "key_length": "3",
          "ref": [
            "cscartdb.pfv.variant_id"
          ],
          "rows_examined_per_scan": 1,
          "rows_produced_per_join": 0,
          "filtered": "5.00",
          "cost_info": {
            "read_cost": "2.17",
            "eval_cost": "0.04",
            "prefix_cost": "27.25",
            "data_read_per_join": "506"
          },
          "used_columns": [
            "variant_id",
            "feature_id",
            "position"
          ],
          "attached_condition": "(`cscartdb`.`fv`.`feature_id` = `cscartdb`.`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": [
            "cscartdb.pfv.variant_id",
            "const"
          ],
          "rows_examined_per_scan": 1,
          "rows_produced_per_join": 0,
          "filtered": "100.00",
          "cost_info": {
            "read_cost": "0.11",
            "eval_cost": "0.04",
            "prefix_cost": "27.40",
            "data_read_per_join": "1K"
          },
          "used_columns": [
            "variant_id",
            "variant",
            "lang_code"
          ]
        }
      }
    ]
  }
}