Repairing crack in concrete screed floor

Hi,

I have a crack in the concrete screed across the doorway between the hall and kitchen.
It is no more than 5mm wide and hasn't changed in a year or so. There are no other cracks in any of the flooring throughout downstairs.

Can I just fill it in with some concrete mix? The google results seem to suggest I need to get special resin etc etc and it looks like a complicated procedure.

I will be having sheet vinyl on this part of the floor.

I was going to leave it as I didn't think it would be much of a problem but someone has mentioned it might show through the vinyl.

Should be ok chip it out a bit with a bolster and fill with ardex A45

Thanks, I have some Everbuild JetCem, is this the same or as good - I'd rather not buy a bag ardex a45 for a one off repair (smallest bag is 11kg it seems)

Yeah should be ok that. You can get a46 in a 5kg but if the jetcem does the same use that