How do I pick an object nearest to a clone with a certain instance variable (Boolean)?

I'm trying to make a hotbar for a game and I want the item that has been bought to go to the nearest available hotbar slot. This hotbar slot has to have a false value for the instance variable "Used". I can get the item and put it in a hotbar slot, but the items just overlap. Basically, I want all items to spawn in the same slot (which I have done), then pick the closest slot that has nothing in it/"Used" set to false.

There is a 'pick nearest' condition

I know, but I want to pick the nearest that has the used value set to false

Can combine as many conditions as you want, so it would be condition 1 : slot.used=false and condition 2 : pick nearest slot to (item?)

Thanks, this helped