EMKA's Program 1500 o ring sealed quater-turn clip-in lock can apparently be fitted, with insert and cam, in 5 seconds.
Program 1500 is a general purpose IP65 lock, ideal for high volume OEM applications, e.g. small boxes, cabinets, enclosures, indoor/outdoor/industrial environments, and fits with an integral insert/cam and lock body with locking fork. It supports most popular inserts: square, double bit and slotted, while others are available on request.
A lower cost version without O ring is also available, where IP65 sealing is not required.