ACF field indexing

I have bought and installed the Ajax-Pro Search Plugin.

Now I’m in the process of building the index table; but I can’t seem to find any place to include my big ACF field in the index.
If I try to search for a custom field (Index custom fields), the functions just hangs, and do not give me any results.
I can choose two othe ACF fields from the Webshop, but nok this one.

I have been through the documentation; but there’s nothing here mentioning ACF fields.

Special about this site:
The site has an ACF Field called “Passer til” in Coocommerce products.
The field contains 4.5 million lines of text, so it’s rather big.

The task is to make a global search field, that can search in all data of this ACF field.

The Webshop is a live Webshop, just for your information.