SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '498ae7905f0324c48387e6ab94a4dfce5b84da6d5af74f23341669c552fd1999' 
  AND token = 'YheBfS43yZg+sMZoCYDe9JcklIn3zdwz7vDURjEjyKU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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