A padlockable pin is designed with a handle, allowing you to secure it with a padlock.

For a simpler solution, consider a key-operated ball lock pin.

This smart block pin functions by using a key to unlock it, enabling you to press the push button to release the connection. In the open position, the balls retract into the shaft, allowing for disconnection.

When locking the smart block pin with the key, the push button becomes inoperable, providing tamper-proof security against thieves.

These are quite large as you can see in the image below: