SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4c28c659690fbbe6bcee4c4430fcef17e4322d023626e94c892cb56a4c546503' 
  AND token = 'DpwobUF5dVTJ+xmw6sV35Ty2vcXs5AJ0xW5ISHSZfcg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}