Do unique promotional codes ever expire?

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Nowadays, I've been seeing promotions that involve two types of codes; a global code (ie. HAPPY-2015)¹ and a unique code (ie. 1234-5678-9012)².

I know that these global codes expire as the expiry date is always stated with their post.
However, there isn't any information about unique ones.

¹ These codes can be used once per account in the given timeframe.
² These codes can only be used once on one account.

I've bought a code through Humble Bundle (Bundle ended, page is out-of-date) and received another as part of the Curse promotions.
I haven't used either of them and I was wondering: Do they ever expire?

So if your code doesn't tell you that it will expire then it won't expire but if you have any problems with it then you should try to contact the Robocraft support them at their site.