Missile Problem

Hi.
I have the following problem
I’m making a SideScroll2D game where you have to intercept enemy missiles.
The idea is that when the missile explodes, the explosion can eliminate those inside its radius, all this for cellular.
I can do that by making a TOUCh on the screen the missile goes to that place, what I still could not do, is that when I get to that place, I’ll do the explosion.
Does anyone know how it could be done?

This is the plane of my character where the missile appears