SELECT 
  cscart_products.* 
FROM 
  cscart_products 
WHERE 
  cscart_products.product_id IN (
    1836, 1336, 1837, 1820, 1304, 1738, 1893, 
    1895, 1894, 1641, 1500, 1317
  )

Query time 0.00090

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": 12,
      "filtered": 100,
      "index_condition": "cscart_products.product_id in (1836,1336,1837,1820,1304,1738,1893,1895,1894,1641,1500,1317)"
    }
  }
}