I wonder how you found out about a job that isn’t posted on a site. Whoever gave you the lead is where I would start.
Let me rephrase this question to help a larger scope of people.
How do you pursue a job that you want, when there’s currently no opening? You create relationships with as many people on the show/project/company as you possibly can. This way when a job does open, you’re top of mind.
1. Create a target list of 10 shows/projects/companies
2. Contact 1-5 people per show/project/company as a mentor
3. Continue to build and deepen the relationships
If you have a question, put it in the comment section.
To your success!