SELECT 
  product_id, 
  feature_id, 
  variant_id 
FROM 
  cscart_product_features_values 
WHERE 
  product_id IN (
    44876, 45036, 45035, 45037, 45038, 45039, 
    45040, 45041, 45042, 45043
  ) 
  AND feature_id IN (24557) 
  AND lang_code = 'vi'

Query time 0.00144

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": "idx_product_feature_variant_id",
          "key_length": "12",
          "used_key_parts": ["product_id", "feature_id", "lang_code"],
          "rows": 20,
          "filtered": 50,
          "attached_condition": "cscart_product_features_values.feature_id = 24557 and cscart_product_features_values.product_id in (44876,45036,45035,45037,45038,45039,45040,45041,45042,45043) and cscart_product_features_values.lang_code = 'vi'",
          "using_index": true
        }
      }
    ]
  }
}

Result

product_id feature_id variant_id
44876 24557 85649
45035 24557 85650
45036 24557 85651
45037 24557 85652
45038 24557 85653
45039 24557 85654
45040 24557 85655
45041 24557 85658
45042 24557 85656
45043 24557 85657