SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5597e0288f950e00ba29f96fdfd4a4c05a788680cb7fa0e08620bb489a8000bf' 
  AND token = 'hZjGf9vnijkjVRxaalVmRbyYgNlIjyXMGEWDNxtjcsc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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