SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4497c91464fc9e0673f43ea43ad0434ae8cbff54086ebba5b25a410a3c58d8e2' 
  AND token = '/0AuSvuPKMnICw47kNYQTrMzQnB7XAAwpVIo7O/IPK8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}