You've just identified why phpMyAdmin should be only accessible through a protected backend like cPanel... or other means.

If Google indexes it, you will be providing a Google Dork, the term for inept server admin mistakes.

Lock down access to it via your .htaccess file with either a login or by limiting the ip addresses that can see the link with a 403 Access denied for everyone else.

Links are to other StackExchange sections where the above protections have been described.