For example you can get a filing cabinet which has a lock and a counter that ticks every time it is opened. You pair it with a clipboard where you note the counter count, why you opened it and sign.

It can be picked, that can't be avoided. But the act of opening it creates a trail which can be detected. Adding a false clipboard entry is detected by subsequent users, there typically aren't many people with access.

Determining that you have a breach allows it to be investigated, mitigated. The lock is an important part of that, but it isn't perfectly secure so you manage that flaw.

Of course filing cabinets are getting rare and replaced by digital document stores, with their own auditing and issues.

But if that's not the threat you are trying to protect against, there are locks that are sufficiently secure that picking or other "low-impact" defeat attempts are considered pretty much pointless. Abloy protec2 comes to mind.

Good locks buy you two things: Deterrence (maybe), and a set minimum of time and noise requirements to bypass them. If your lock reputably takes 3 minutes to pick or a Ramset gun to blast them open, make sure your guard comes by every two minutes, and otherwise stays in earshot.

Virtually any lock can be destroyed with tools and most doors/walls can be busted through with enough effort and equipment. I think the airport police would notice that, though ;)

If secure means "without leaving evidence of tampering," things get a lot more interesting, but that has narrow practical use cases outside of stuff like espionage. Once you're in this space, we can start talking about how difficult something can be without specialized tools. But now we're leaving "I am protecting my stuff" territory and entering "this is just a sport and we're agreeing on a ruleset" territory.

There are a couple of lock designs out there that I don't think anybody's successfully ever picked. The ones that first come to mind are a couple of the "smart" electronic locks. Many of those are junk, but a few are very well thought out.

There are always assumptions built into lock design. A simple lock is very secure if a fence is jumpable, most people will jump the fence rather than mess with a lock.

Even a complex lock will never be secure for national secrets (like nuclear missiles), you need to just assign guards. Locks exist but are basically a formality (IIRC, many tanks and airplanes are left unlocked because all the security posture is with the military and the lock itself is too much of a hassle for logistics).

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Fort Knox itself was designed to be safe from Nazi invasion. If the Nazis invaded New York City, they won't find any of the governments gold. The 'lock' in this case is the miles and miles of geography the Nazis would have to navigate before reaching Fort Knox.

You need to be more specific with what "truly secure" means.