SELECT 
  cscart_products.* 
FROM 
  cscart_products 
WHERE 
  cscart_products.product_id IN (
    1666, 1665, 1663, 1660, 1662, 255, 1661, 
    1658, 1657, 1656, 1655, 1654, 1653, 
    1652, 1651, 1650, 1324, 1647, 1646, 
    1645, 1643, 1642, 1641, 1640
  )

Query time 0.00073

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": 24,
      "filtered": 100,
      "index_condition": "cscart_products.product_id in (1666,1665,1663,1660,1662,255,1661,1658,1657,1656,1655,1654,1653,1652,1651,1650,1324,1647,1646,1645,1643,1642,1641,1640)"
    }
  }
}