Translation:The tobacco shop is open, do you come in?
It is a highly irregular 'verb', so it would be "trafok".
And its past tense is also irregular: "dohánybolt".
Not to worry, there are much better jokes where this came from. :)
"Do you come in" is not normal British English usage - "are you coming in" is better.
Yes, I haven't heard the word 'trafik' here since the new legislation on national tobacco shops.
Is 'trafik' used only for stand with tobacco? What's the name for stand with newspapers, tickets, etc.?
I think we'd use tobacconist or tobacconist's rather than tobacco shop, in England.