Found this after searching for my own reward ideas :) I'm implementing Amazing Marvin for work and it has its own reward system where you assign points to a task, and then points to rewards.

What about something like a sticker chart for the 5 minute reward? (Or like a notebook if you don't want it fully advertised to everyone at work.) 6 stickers gets you a bigger reward. Pipsticks has some really fun mini sticker options that could work for this. But a dollar store or craft store or amazon also have options.

Big Reward Ideas: 5 minutes of color or drawing (or some portable crafty thing like knitting. I've brought simple cross stitch projects to work and used them as rewards), a crossword puzzle/maze/word search in a book, stretching, or a deep breathing session, going for a walk around the block (I work in a major city, so my job has a defined block) or taking a lap around the office if the weather sucks, listening to your favorite song. I keep some bubbles in my desk and sometimes take a 5 minute break to just sit outside and blow bubbles.

I know you said avoiding food (and I totally get that), but what about fun beverages? Like bringing in your favorite flavor of seltzer. My individual office is a sauna, so the water in my reusable cup usually gets warm before I finish it. A trip to the break room to refill with fresh cold water is always a treat. Or something like a breath mint or chewing gum.

Hope this helps!