Clark does check his pulse and eyes as he says that single sentence. Not because he thinks Bruce would hide Kryptonite from him if it was in this place, but because he's yet to see Bruce give up his little ring of Kryptonite away.

But he's always been trustful, and he's all too eager to believe in a world without Kryptonite. The green glowing mineral makes him feel too uneasy in his new homeworld already, having it in this unknown place where Bruce is alive, Kon is his 90s self and nobody seems to trust anybody else... it would be a little too much.

So a simple "Thanks, B." is all the reply he gets.

"I tried my laser vision and ice breath in the wall both, if it makes a difference."