Lost keys for job. Any advice?

I'm taking over as the DSD reciever at my job for a week, since the usual reciever is on vacation. Unfortunately, I've lost a set of important keys for the job. I've tried looking for it in my room, since the keys were attached to my pants, but I can't find them. I already let the usual reciever and the manager of the store know. The manager doesn't want to let Loss Prevention know, because he says they'll go "ape-****," but I don't think I'll find the keys like he wants me to. The only other place they could be would be somewhere on the floor between my job to my house--since I normally walk to work; I've already tried retracing my steps to look for them and I haven't found anything. I'm thinking of putting up signs and offering a reward for the keys, but we honestly need a new set of keys and locks for the store anyway. Don't get me wrong; I know losing the keys is no excuse for me to point out that we need new locks. I've just been having a terrible week and I'm really confused as to what to do. Any advice?