SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '6a2d8caf31e33445a6ea383fa77a03addceec4688992957cbe417eeb5d5d96d4' 
  AND token = '1C9IP5lMPDBrCYHmKDDNZP0oX9yCaQf5tlO/qIxEmh0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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