SELECT 
  product_id, 
  feature_id, 
  variant_id 
FROM 
  cscart_product_features_values 
WHERE 
  product_id IN (
    13009, 13010, 13011, 13012, 13013, 13008, 
    13007, 13006, 13005, 13004, 13003, 
    13002, 13001, 13000
  ) 
  AND feature_id IN (
    646, 647, 595, 628, 627, 624, 625, 553, 
    626, 622, 623, 636, 637
  ) 
  AND lang_code = 'en'

Query time 0.00871

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "11.09"
    },
    "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": "PRIMARY",
      "used_key_parts": [
        "feature_id",
        "product_id",
        "variant_id",
        "lang_code"
      ],
      "key_length": "15",
      "rows_examined_per_scan": 32,
      "rows_produced_per_join": 32,
      "filtered": "100.00",
      "using_index_for_skip_scan": true,
      "cost_info": {
        "read_cost": "7.89",
        "eval_cost": "3.20",
        "prefix_cost": "11.09",
        "data_read_per_join": "24K"
      },
      "used_columns": [
        "feature_id",
        "product_id",
        "variant_id",
        "lang_code"
      ],
      "attached_condition": "((`test2_gaseus`.`cscart_product_features_values`.`product_id` in (13009,13010,13011,13012,13013,13008,13007,13006,13005,13004,13003,13002,13001,13000)) and (`test2_gaseus`.`cscart_product_features_values`.`feature_id` in (646,647,595,628,627,624,625,553,626,622,623,636,637)) and (`test2_gaseus`.`cscart_product_features_values`.`lang_code` = 'en'))"
    }
  }
}

Result

product_id feature_id variant_id
13000 553 1973
13001 553 1973
13002 553 1973
13003 553 1973
13004 553 1973
13005 553 1973
13006 553 1973
13007 553 1973
13008 553 1973
13009 553 1973
13010 553 1973
13011 553 1973
13012 553 1973
13013 553 1973
13000 595 1904
13001 595 1904
13002 595 1905
13003 595 1905
13004 595 1789
13005 595 1789
13006 595 2499
13007 595 2499
13008 595 1787
13009 595 1787
13010 595 1900
13011 595 1900
13012 595 1899
13013 595 1899
13000 622 2497
13001 622 2497
13002 622 2497
13003 622 2497
13004 622 2497
13005 622 2497
13006 622 2497
13007 622 2497
13008 622 2497
13009 622 2497
13010 622 2497
13011 622 2497
13012 622 2497
13013 622 2497
13000 623 2501
13001 623 2501
13002 623 2501
13003 623 2501
13004 623 2501
13005 623 2501
13006 623 2501
13007 623 2501
13008 623 2501
13009 623 2501
13010 623 2501
13011 623 2501
13012 623 2501
13013 623 2501
13000 624 1803
13001 624 1803
13002 624 1803
13003 624 1803
13004 624 1803
13005 624 1803
13006 624 1803
13007 624 1803
13008 624 1803
13009 624 1803
13010 624 1803
13011 624 1803
13012 624 1803
13013 624 1803
13000 625 2123
13001 625 2123
13002 625 2123
13003 625 2123
13004 625 2123
13005 625 2123
13006 625 2123
13007 625 2123
13008 625 2123
13009 625 2123
13010 625 2123
13011 625 2123
13012 625 2123
13013 625 2123
13000 626 1879
13001 626 1879
13002 626 1879
13003 626 1879
13004 626 1879
13005 626 1879
13006 626 1879
13007 626 1879
13008 626 1879
13009 626 1879
13010 626 1879
13011 626 1879
13012 626 1879
13013 626 1879
13000 627 1659
13001 627 1659
13002 627 1659
13003 627 1659
13004 627 1659
13005 627 1659
13006 627 1659
13007 627 1659
13008 627 1659
13009 627 1659
13010 627 1659
13011 627 1659
13012 627 1659
13013 627 1659
13000 628 1660
13001 628 1660
13002 628 1660
13003 628 1660
13004 628 1660
13005 628 1660
13006 628 1660
13007 628 1660
13008 628 1660
13009 628 1660
13010 628 1660
13011 628 1660
13012 628 1660
13013 628 1660
13000 636 2348
13001 636 2348
13002 636 2348
13003 636 2348
13004 636 2348
13005 636 2348
13006 636 2348
13007 636 2348
13008 636 2348
13009 636 2348
13010 636 2348
13011 636 2348
13012 636 2348
13013 636 2348
13000 637 2345
13001 637 2345
13002 637 2345
13003 637 2345
13004 637 2345
13005 637 2345
13006 637 2345
13007 637 2345
13008 637 2345
13009 637 2345
13010 637 2345
13011 637 2345
13012 637 2345
13013 637 2345
13000 646 2369
13001 646 2370
13002 646 2369
13003 646 2370
13004 646 2369
13005 646 2370
13006 646 2369
13007 646 2370
13008 646 2369
13009 646 2370
13010 646 2369
13011 646 2370
13012 646 2369
13013 646 2370
13000 647 2373
13001 647 2374
13002 647 2373
13003 647 2374
13004 647 2373
13005 647 2374
13006 647 2373
13007 647 2374
13008 647 2373
13009 647 2374
13010 647 2373
13011 647 2374
13012 647 2373
13013 647 2374