How do I find the correct meta key of a field [RESOLVED]

I am using GFAPI::get_entries() with search criteria.
However I don’t think I have the right meta key added to my search criteria.
I added the paramater name to that field as franchise_page_id.
How would I be able to find the name of the meta key for a specific field on a form with that parameter name?

I know that the field is number 15 and key => '15' works in the search criteria but not with franchise_page_id.

        $search_criteria = array(
            'status'        => 'active',
            'field_filters' => array(
                'mode' => 'any', // Get any of these key value pairs
                    'key'   => 'franchise_page_id',
                    'value' => $user_franchisee_id
        $result = GFAPI::get_entries( 1, $search_criteria );

The field parameter name setting is only used for dynamic population on form display. To search the entries, you need to use the field ID (key => '15').

Under the docs in the Field Filter section it says I can use

The field ID, entry property, or entry meta key.

It looks like I’ll have to add Entry meta first via the gform_entry_meta hook and then I will be able to access it.
Looks like my issue is solved.