Skip Existing Product

I now it is an option for that

When we import csv and product existing on cscart to skip these product…not to change that product

i don`t now where is

At 4.2.4

If you have the same data in your csv as you have on your site then it won't matter if it's updated.

There is no provision in an import for “new products only” that I'm aware of.

Custom modification of your cart would be required.