SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6809ed9c8a8827bdc1ffa5ea262e65a37ee8aa0fe2696807c28b5ee49fda64f8' 
  AND token = 'bowcKGW0YzQiKjUQHmXCuv7URUQVO3he+IqFjqzD/7g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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