SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1b9b519dc8a7693dfa97a8223b4f045355eba5e1c3ab50d67354504986d5cd23' 
  AND token = 'CMXmAVDLFF66lf6KH7t1NhFC9ipVFFdHTf4zt9APz5M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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