Is it possible to distribute an unfinished iOS app for closed-beta tests using Apple Store?

It is possible now to use TestFlight Beta Testing, with a current limit of 1,000 invites and without the need of asking and registering UDIDs.

Simple answer. No.

Detailed answer. No, Apple requires that applications in the app store be final products. You can attempt to slip it through so long as you don't call it a beta or make any reference to it not being completed. In doing this method you are skirting Apple's rules which could result in having your developer license revoked.

More information can be found HERE--> https://developer.apple.com/app-store/review/guidelines/ <--HERE

Edit to add: No you can't disable reviews in tha app store.

Beta test apps are explicitly prohibited by Apple's App store guidelines.

However if you don't explicitly label or advertise an app as Beta test, and the app appears fully functional and otherwise acceptable, then Apple might approve the submission.

It is actually quite common for developers to submit unfinished apps and put them in the App store (see the "minimum viable product" style of development). However the unfinished features have to not be apparent and not mentioned anywhere in the apps description or documentation, so that the app appears to be fully functional to the reviewers (e.g. if some feature is missing, then hide the button and documentation for it so that no one knows that something is missing). I've got an app in the App store that only has 5 or so of the many dozens of features on my original design spec. No one knows (until now :)

There is no way to limit app downloads to only specific testers (other than using Ad Hoc, Enterprise or B2B accounts) for closed testing, and there is no way to prevent bad reviews and ratings. You can limit app availability by country and by day, and submit no search keywords to limit exposure. You could try pricing your app too high and gifting the app to your testers if you are willing to give Apple 30% of the high price per copy.