SELECT 
  cscart_products.* 
FROM 
  cscart_products 
WHERE 
  cscart_products.product_id IN (
    4024, 4020, 4028, 4037, 4019, 4029, 4036, 
    4025, 4042, 4026, 4045, 4038, 4046, 
    4040, 4039, 4022, 4021, 4041
  )

Query time 0.00036

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "table_name": "cscart_products",
      "access_type": "range",
      "possible_keys": ["PRIMARY"],
      "key": "PRIMARY",
      "key_length": "3",
      "used_key_parts": ["product_id"],
      "rows": 18,
      "filtered": 100,
      "index_condition": "cscart_products.product_id in (4024,4020,4028,4037,4019,4029,4036,4025,4042,4026,4045,4038,4046,4040,4039,4022,4021,4041)"
    }
  }
}