$this->executeAfterSeconds(5);
If it was a third-party library or I was able to refactor the method itself I would go for constant named after what it represents, rather than what it is: $this->executeAfter(FIVE_SECONDS);
As a last resort (like if you had some reason why would couldn't physically change the source) a comment would also be totally acceptable.
I had to think about the first one for a moment, but I do agree. It's better to abstract later with greater knowledge than the much more difficult task of trying to debug or fix it later.
It's an outstanding list and great rules to work by!