SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4ee883637ae6d21650973c0643282cce510d46f767dc07484c43ff369e40dabc' 
  AND token = 'ErIgC3kU3alkSFpZU7j6C7gHXgqk4L6wyx2xVRkKnSA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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