There is always something that has to be completed in exactly 5 minutes: cooking eggs, workout set, removing teabag...
This is a small utility I needed for this purpose but could not find one with the user experience that good enough had exactly one tap away from setting the alarm without overhead of widget.
Today we have Google Now for this purpose and when I want to set reminder to 5 minutes I just need to do following steps:
App has not been updated since 2012 but if you still want it go to 5min at Google Play Store