2D Physics in a 3D world

Is it possible to use 2D physics in a 3D environment? Or is there any limitation like it only works in a Canvas or in a 2D setup?

My game is 3D but the target systems (the attack range of the units) is just a Radius from the center of the Unit. If I add a 2D Circle Collider component, will it detect collisions among other 2D Colliders?

Units always move in the exact same height/plane (Y axis).