I found the tests can be deceiving for some, but all your numbers look great (So nothing deceiving there). Friend of mine in his 60's also had zero calcium, but had triple-bypass surgery (almost died) not long after.
I scored over 400 myself (which can be alarming), and then did all the intrusive follow-ups (stress-echo, nuclear-stress test), said mine was from statins doing their job, calcifying potential plaque, no blockages, ejection fraction of 65% which is great, normal heart, no valvular disease, etc. All tests came back as very good/normal.
With your other numbers and that score of zero, I have no doubt you have nothing to worry about. Mine came from very high lipids (familial issue) and statins doing their thing.
Looking good...