Make your shake at night and keep it in the fridge. I have all my food for the next day ready the night before. As others said: you gotta have everything ready the night before if you don't have flexible hours. It's a pain since you're tired and don't want to, but that's just the best way to deal with the unexpected.

Or, I eat breakfast at work, so that's an idea: invest in a shaker bottle, and just throw the protein powder in there. When you get to work put water in it and shake it up and drink it while you're working. Or even better, I keep my shaker bottle at work and protein at work, if you can do that.