SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2b9a70451e515eef19705bb831b8b315cfe397306f8a914f5551dc5eafc18260' 
  AND token = 'dM2tFS74UiOm4ABCFVbFc5ciJy24IUI+lfUNN5OmWIQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

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