Do you have these binoculars in black?
A pair of eyeball mirrors - that's binoculars. Binoculars have mirrors in them to allow you to see through the pair of eye holes, which is how this word makes sense.
The 鏡 part uses the on'yomi reading, which you didn't learn. To remember this, just think about how when you look down binoculars, you see something strange (like a strange reading for 鏡). That strange thing you see through these fantastic binoculars is... tomorrow. Your binoculars are so strong that you can already see tomorrow, today (きょう)!