The keycard can be found in: The storeroom. A storage room affected by SCP-970. The 2-level office, next to a computer. The keycard can also be created by putting a quarter into SCP-914 on the "Fine" setting. Level 2 Level 2 keycards can be used to open the doors to SCP-895 's chamber and SCP-914 's chamber. The keycard can be found in:
Full Answer
Green keycards are very common and you can easily find them first as they respawn every half an hour or so. You don’t even need any other keycard to access these. They not only spawn in predictable locations but they can also be found on the bodies of Scientists (the AI blue hazmat guys) at rare times.
Blue keycards are a little harder to get as you will first need a green keycard. Here’s where you can find the blue keycard in Rust:
The most valuable type of keycard are the red ones and they are the hardest to get. They also get you the best loot. Red keycards will always need you to have a fuse, a blue keycard, and sometimes even a green keycard. So you need to get the green and blue cards first.