Search in all emails for string

Is there any way to do a search or a smart list that will search all files, or emails and landing pages for a character string?

I'm trying to do clean up of old tokens that are no longer needed, but they're used by old programs, and I don't want to have to go through each and every one just to find the token so I know what to edit. Otherwise I can't delete the token - it'll say "Token in use"