On sand you'll need wider tires that do not dig into sand as easily as well as some tread pattern to prevent sand grains from rolling under your tires. 23mm is too narrow.
Measure the forks, if they are wide enough you can use cyclocross semislicks. I have seen an old Trek road bike with cyclocross tires used in a race, so it might be possible for your bike too. Narrower touring tires are an option too, get the widest that you can fit.