Depends on which type of escorts you are looking for.
I'm East Asian (but I've been told I look more like a Southeast Asian), so in my own experience, I've never been denied by any agency or indie SP in Van.
Most Asians shops will have ads where they explicitly say "No brown or black" clients for some of their ladies. If they don't I would the assume they're open to everyone. But it's best to ask just in case.
I don't ever recall seeing this type of restrictions in "Western" agencies, so that would be your best bet.
Never meet anyone off of craiglist or backpage, so no clue there. LL I've limited experience.