It's present, and means "wants to". However... The singer and writer is not a native English speaker, and to be honest I don't think a native speaker would ever use a phrase like that. The reason you don't find "wanna" in your dictionary is that it isn't a word. It's a slurred way of saying "want to/want a". Don't use it in writing, and be very careful about using it in speech. Just use "want to" and you'll have no problems.

"Wanna"="Wants to"