You can use mairix as a search system outside of mutt. Results are a temporary mailbox.
http://git.notmuchmail.org/git/notmuch/blob_plain/HEAD:/cont...
However, in my experience mutt-kz is much faster. Plus, you get tagging everywhere (if you use it) and threads can be reconstructed across folders (helpful when your own mails are in a 'Sent' folder).