They'll both turn up when you don't expect it. But right now it must be mega-annoying.
I'll keep my fingers crossed that at least one of them turns up soon.
I have about a dozen of these little USB sticks, some for work, some for personal stuff. I have just put really big and colourful shapes on them so that I find them more easily when (and that happens often) I misplace them. I just use a leftover piece of that stiff and sticky interfacing that's used for making fabric postcards, cover both sides with a bright and cheerful scrap of fabric, sew around the edges with a satin stitch, make a hole with a punch and a one of these metal grommits, thread a piece of ribbon through the 'USB Stick Keeper' and the USB Stick, and job done! I do the same with rotary cutters, scissors, and rulers. It's too easy to 'lose' them, and they are expensive to replace.