I wanna buy new bmx tires
 

I bought WTP complete bike with 20 x 2.35” tires and I wanna know if I can use new tires that are 20x 2.40”?
On top of the tires I have about 0.52 inches room

The rim sizes are the same for all 20" tires (406), with the exception of a couple of very narrow tires (451).

You say you have about 1/2" of clearance. Your new tire is listed as about 1/20" larger, so you'll probably hardly even notice the size difference, and it could fall within the random variability of tire carcasses from brand to brand.

Anyway, your new tires should be fine.