SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4322238fc742b505518c75a5f64c5bfd0940ccbbb686a54a9cd26d1494079ab9' 
  AND token = 'y4BTvxByYSuYq7VoZom8HbWhwvcNLFCYDxKar9rT0VU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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