SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'de9938547bbe0591fe75ed5821ac43e9852c36981ba6403e21e319d38bc7f73a' 
  AND token = 'F8S1shFS8vmlr8BBIqmHG51GQtk2iNwmHxXjD5XI5/4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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