2 things. I've heard from some users that none of their custom shortcuts remained when copying to CC from no CC versions. The other thing is some keyboard shortcuts have chnaged since CS5.5 and many many new ones have been added so it may make sense to start from scratch with CC.
I don't have CS5.5 loaded on my machine so I'm not 100% sure the file is located here but you can give it a shot.
Copy your .kys file from
/Users/[username]/Library/Application Support/Adobe/Premiere Pro/5.5
and paste to