From what I can determine, Jon Spencers Blues explosion is who plays it.
Can you or anyone who reads this.. go to http://search.playlist.com/tracks/blues-explosion or their website http://www.thejonspencerbluesexplosion.com/ and find which one of those songs might be the one they use on the show? If you can find it, I can make it.
All I could find out was that it was from John Spencer's Blues Explosion but I can't be for sure.
If anyone knows for sure who the artist is.. let me know.