I can think of two English expressions: "dead wood" and "clock watchers."

In general, "dead wood" is more often used for people who have reached a level that makes it difficult to fire them, at which point they choose to become lazy and unproductive. You wouldn't normally say it about an entry-level employee, however, because generally it's easy to fire such people if they're unproductive.

"Clock watcher" is self-explanatory, I think, and can be used for a person of any level whose job is (seemingly) to sit and drink coffee.

Also, Mr. Burns on The Simpsons used the self-explanatory expression "chair-warmer" to describe Homer's job.

And then there's "Bubble" from Absolutely Fabulous, whose job was "dunno... git paid."

I really love the expression офисный планктон. Does this possibly have some connection with the meme "йа -- краведко"?