SELECT 
  product_id, 
  feature_id, 
  variant_id 
FROM 
  cscart_product_features_values 
WHERE 
  product_id IN (
    11298, 11297, 11296, 11295, 11294, 11293, 
    11292, 11291, 11290, 11289, 11288, 
    11287, 11286, 11285, 11284, 11283, 
    11282, 11281, 11280, 11279
  ) 
  AND feature_id IN (553, 624, 623) 
  AND lang_code = 'en'

Query time 0.00282

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "16.26"
    },
    "table": {
      "table_name": "cscart_product_features_values",
      "access_type": "range",
      "possible_keys": [
        "PRIMARY",
        "fl",
        "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": 70,
      "rows_produced_per_join": 70,
      "filtered": "100.00",
      "using_index": true,
      "cost_info": {
        "read_cost": "9.26",
        "eval_cost": "7.00",
        "prefix_cost": "16.26",
        "data_read_per_join": "54K"
      },
      "used_columns": [
        "feature_id",
        "product_id",
        "variant_id",
        "lang_code"
      ],
      "attached_condition": "((`gaseus`.`cscart_product_features_values`.`product_id` in (11298,11297,11296,11295,11294,11293,11292,11291,11290,11289,11288,11287,11286,11285,11284,11283,11282,11281,11280,11279)) and (`gaseus`.`cscart_product_features_values`.`feature_id` in (553,624,623)) and (`gaseus`.`cscart_product_features_values`.`lang_code` = 'en'))"
    }
  }
}

Result

product_id feature_id variant_id
11279 553 1324
11279 623 1983
11279 624 1705
11280 553 1324
11280 623 2095
11280 624 1705
11281 553 1324
11281 623 2096
11281 624 1705
11282 553 1324
11282 623 2097
11282 624 1705
11283 553 1324
11283 623 2085
11283 624 1705
11284 553 1324
11284 623 2086
11284 624 1705
11285 553 1324
11285 623 2087
11285 624 1705
11286 553 1324
11286 623 2088
11286 624 1705
11287 553 1324
11287 623 2089
11287 624 1705
11288 553 1324
11288 623 2090
11288 624 1705
11289 553 2197
11289 623 1983
11289 624 1705
11290 553 2197
11290 623 2095
11290 624 1705
11291 553 2197
11291 623 2096
11291 624 1705
11292 553 2197
11292 623 2097
11292 624 1705
11293 553 2197
11293 623 2085
11293 624 1705
11294 553 2197
11294 623 2086
11294 624 1705
11295 553 2197
11295 623 2087
11295 624 1705
11296 553 2197
11296 623 2088
11296 624 1705
11297 553 2197
11297 623 2089
11297 624 1705
11298 553 2197
11298 623 2090
11298 624 1705