Otherwise you can do them as save up the keys for future updates (like the two new dunegons coming soon) and open lots of chests then.
@Turelus - EU PC Megaserver "Don't count on others for help. In the end each of us is in this alone. The survivors are those who know how to look out for themselves."
There's more monster sets coming, so you could could continue doing pledges for keys. It's a bit of a chance because the monster sets may not be better than what you have, but you never know.