SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '03ed5e06162408b90492ba3588b31f04d6f3dcdf10e29c49856f2483aee6e4c6' 
  AND token = 'IxG/wZMDD2nmjnhgAtNnrL9WLORr+CEDtjVoRS7pmic=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}