Collisions and their related events will only work in either Play or Simulate. However, there are ways to integrate something like this on your own but keep in mind it will cost you performance in the editor. This is why I would recommend easy overlap tests like calculating the distance or using a simple linetrace in an already known direction e.g.
You could combine something simple like that with the ‘editor tick’ How to do editor tick via utility widget? - #2 by ClockworkOcean