Just leave a stream on overnight that has "Drops Enabled" underneath their stream.
Make sure you have the Twitch audio turned up though, even just a little bit, as muting the stream essentially "takes you out of the running".
I left my computer on for 2 nights (not during the day) and I was able to obtain a key. There are several 24-hour streams going on, such as Anomaly's stream, in which they just replay old VOD's.
Good luck!