SELECT 
  product_id, 
  amount 
FROM 
  cscart_warehouses_destination_products_amount 
WHERE 
  product_id IN (
    507, 509, 481, 510, 511, 449, 482, 513, 
    484, 492, 493, 494
  ) 
  AND destination_id = 11 
  AND storefront_id = 0

Query time 0.00018

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost": 0.00345856,
    "nested_loop": [
      {
        "table": {
          "table_name": "cscart_warehouses_destination_products_amount",
          "access_type": "ref",
          "possible_keys": ["PRIMARY", "idx_storefront_id"],
          "key": "idx_storefront_id",
          "key_length": "3",
          "used_key_parts": ["storefront_id"],
          "ref": ["const"],
          "loops": 1,
          "rows": 1,
          "cost": 0.00345856,
          "filtered": 100,
          "index_condition": "cscart_warehouses_destination_products_amount.destination_id = 11 and cscart_warehouses_destination_products_amount.product_id in (507,509,481,510,511,449,482,513,484,492,493,494)"
        }
      }
    ]
  }
}