Enchantment tables are very valuable, so you need to hide them well. To do this, you can take advantage of the fact that enchantment tables from below have the same texture as obsidian.
If you have a lava lake made into obsidian and dig under it (for whatever reason), you can make it a great hiding place.
Instructions:A magic table has the same texture as obsidian from below, so you can put it in a blanket of obsidian without seeing it, moreover you can make books on the obsidian all around, so you can enchant to maximum. Furthermore there is a hidden crate made of a minecart with a crate that is pushed into a wall with a piston. In this hidden crate you can hide the necessary lapis to enchant. I put a crate in front of it as a distraction because the minecart was peeking out of the wall.
Here's another picture from below (the enchantment table is second from the back and from the right):