No, this isn't an example of casual racism.
First, if it was "Honest Steve", I assume you wouldn't see it as racist? Or "Honest Mary", the same? If so, how about "Honest Vinnie"? Is it only when the name suggests a specific ethnic or racial group that it feels racist to you? Only certain such groups?
That actually reveals a bigger problem. If "Steve" and "Mary" are 'normal' names, but "Achmed" (and maybe "Vinnie") is 'weird'/'noticeable' to you, then that's a hidden assumption that "normal" = "white middle class American". That's not good.
The second major issue is that there's a subtext to this joke. The joke is that no one in the US would call a new CA "Honest Achmed", precisely because it looks... odd. In other words, the joke is on the people that find it odd - including the same people that think it might be a racist joke. That it feels 'odd' is wrong; it shouldn't. But in our society, it does feel odd. That's not the joke being racist - that's society being biased. When you call the joke racist, you're completely missing the point, and shooting the messenger.
Am I saying stuff like this can never be racist? Of course not. It could easily be. If a TV show always picks a black person for the "random criminal of the week", that's racist. Likewise, if every time we needed a random name of "new CA" it was an Arab-sounding one, that would be racist. In other words, the pattern matters. When a TV show or a recurring joke constantly focuses on one group, for no reason, that's very possibly wrong.
But of course, we don't constantly use Arab names for "new CA" jokes. There isn't such a pattern. This is just a one-off joke. One that actually makes fun of the racism you're worried about.
Worrying about racism is a good thing. But seeing racism where it isn't is not, it's the opposite.
