Quote the entry key when looking for it.

This avoid matching the special characters like + that are allowed
by the bibtex format.

I encountered this problem with the artcicle http://onlinelibrary.wiley.com/doi/10.1111/j.1742-4658.2008.06844.x/abstract;jsessionid=3A67D34CF33478C44A6B3433637E5E77.f01t03

Its id is "AFK+09", then it made the command (re-search-forward (format "^%s " (ebib-cur-entry-key))) fail.