This might be terrible advice, but I heard a trick that was supposed to help highly-intelligent people with ADHD: take a dopamine break. The idea is that dopamine would also boost executive function. (The real question is where you get the dopamine, but some suggestions were taking a walk.) In general (and for the same reason) you should make sure you're getting enough exercise -- and also enough sleep.

I also had a friend that used to play short games online -- minesweeper, Spider Solitaire, whatever -- and swore that the quick game breaks were part of his "process" (maybe to bring dopamine levels back up)? But this is very hard to explain to co-workers...

For the more general problem of restoring focus: I've tried spending entire days offline -- or at least big chunks of the day. (Take a hike! Read a book! Visit friends live and in person...) Meditation exercises might actually help a bit, but this gets into more general wellness.

And I guess your last option is, of course, to tell your boss that you find the work boring, or, to look for a more interesting job. It's been my experience that sometimes just reminding yourself that you have that option relieves some of the pressure.