The LEGO Movie 2: How to unlock Coffee Unchained?
It turns out that Coffee Unchained is actually not a quest in Apocalypseburg. Instead, the Apocalypseburg shop where you can buy a Master Piece is the building simply labeled "Shop", North of the Liberty Statue. This is the building onto which you shoot stickers in a side-quest.
The page I linked to in my question doesn't specify the world, which caused me some confusion. After checking some guides it became clear.
This guide to Apocalypseburg mentions nothing about Coffee Unchained. Instead, it is one of the quests in Syspocalypstar. According to the guide to Syspocalypstar one must:
Speak to the guy in front and he'll ask you to build four "Blue Chairs" and two "Outdoor Tables". Next, get him the three items: "Donut", "Croissant", and "Pretzel". These can all be bought in Classic Bricksburg. Return them to him.
I had assumed there would be a way to eventually unlock Coffee Unchained in Apocalypseburg because it's part of the story of that world, and is featured in the movie as a defining landmark of the city. But in the game it is reserved for later when you build it in Syspocalypstar and it has its own little side-quest there.
In Apocalypseburg, both the Shop and Coffee Unchained are locked the first time you play through. After building a regular shop in Syspocalypstar, the Shop in Apocalypseburg opens up, while Coffee Unchained does not.