I'm not affiliated with them or anything... But Paclock is a fairly well respected medium security lock company that assembles their locks in the US.
They have a model specifically designed for job boxes and they specify that they fit the rigid boxes https://www.amazon.com/PACLOCKs-Job-Box-Lock-American-Compliant-Stainless/dp/B07WMST9YH/ . Not super cheap at damn near $40 each, but probably worth it.
And Bosnianbill approved. https://youtu.be/-akZvzvtTEA
https://www.amazon.com/dp/B07WMST9YH/ref=cm_sw_r_cp_apa_i_iXniFbFYPFMYY