SELECT 
  cscart_products.* 
FROM 
  cscart_products 
WHERE 
  cscart_products.product_id IN (
    65535, 65674, 65465, 65418, 65536, 65423, 
    65455, 65700, 65453, 65625, 64815, 
    65691
  )

Query time 0.00066

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,
      "attached_condition": "cscart_products.product_id in (65535,65674,65465,65418,65536,65423,65455,65700,65453,65625,64815,65691)"
    }
  }
}

Result