SELECT 
  product_id, 
  feature_id, 
  variant_id 
FROM 
  cscart_product_features_values 
WHERE 
  product_id IN (
    47277, 47330, 47321, 47329, 47322, 47323, 
    47328, 47324, 47327, 47325, 47326
  ) 
  AND feature_id IN (24780) 
  AND lang_code = 'vi'

Query time 0.00215

JSON explain

{
  "query_block": {
    "select_id": 1,
    "nested_loop": [
      {
        "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",
          "key_length": "6",
          "used_key_parts": ["feature_id", "product_id"],
          "rows": 12,
          "filtered": 91.66666412,
          "attached_condition": "cscart_product_features_values.feature_id = 24780 and cscart_product_features_values.product_id in (47277,47330,47321,47329,47322,47323,47328,47324,47327,47325,47326) and cscart_product_features_values.lang_code = 'vi'",
          "using_index": true
        }
      }
    ]
  }
}

Result

product_id feature_id variant_id
47277 24780 86432
47321 24780 86441
47322 24780 86442
47323 24780 86433
47324 24780 86434
47325 24780 86435
47326 24780 86436
47327 24780 86437
47328 24780 86438
47329 24780 86439
47330 24780 86440