It doesn't matter if it is pasteurized. Just no preservatives. Ascorbic, Citric, and Malic acid are OK, but nothing else.
Pretty much any Grocery store should have what you want. Just double check the ingredients, and if it has anything like ''sorbate' on the ingredient list, leave it alone.
I know it seems as though the product would be better if you get a 'cloudy' cider, but some of them take forever to clear. Some may argue you get better flavor with the cloudy cider, but I can't say I've noticed any difference in the finished product. WholeFoods 365 Juice never clears. Clear apple juice will do fine and no issues with clearing.