Yes, CC622 will work with PHP 7.2.
Be aware, however, plugins provided by some third-parties will need to have new versions replace older versions. These plugins require the ionCube loader, and ionCube is such that there are specific versions of the loader for respective versions of PHP, and also that PHP code that requires the loader be "compiled" against that specific version of the loader being used.
That is, if upgrade PHP, then also upgrade the ionCube loader to match, then the plugin author will need to recompile their PHP scripts against that new loader version, and the plugin user replaces the previous version of the plugin with the new version.
Also, there are PHP extensions that CubeCart 622 needs that have, on the rare occasion, not been enabled with PHP 7: ZIPArchive and MBString.
So, in admin, PHP Info, scroll through the tables verifying the presence of these extensions.