SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bccd574f889cd421f631d98abd817b6d73dbc050acc289dbd1bf0c09ef18c044' 
  AND token = 'ThtVfASU1418wXN4JPj8hDIcaTnisf0gY7pHY/uSZdI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00061

JSON explain

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