SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'a05d8e58ad6d9ad32f4886f911a34df0831916b59953242f73060610983c1b17' 
  AND token = 'zOw6QrS0WU5tsLX+WPK/wU1ZBdh+/bnrvMIfPXg7Ttk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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