You can't. No third party can tell you about what is going inside Google's black box.

GSC is the most reliable source but it it only shows the links it has discovered and knows about and that includes nofollowed links.

GSC does not tell you what links are indexed nor does it tell you what links are counting nor does it tell you all the links that Google knows about.

[edited by: martinibuster at 5:36 pm (utc) on Sep 30, 2022]

Search on the urls to see if Google has indexed them. There is a lag between indexing and showing up in GSC.

You can check link indexing using google search console.

As martinibuster explained last April:

GSC does not tell you what is indexed nor does it tell you what links are counting nor does it tell you all the links that Google knows about.

That is still true today. Pretty useless for the purpose of checking link indexing reliably.

Following up:
One can search for the URLs to see if Google knows about them, but that doesn't tell you anything about how Google is using those links.

You can check if the page is cached but that still doesn't help you understand if the link has been folded into the Link Graph [searchenginejournal.com] or excluded from the Link Graph.

Google discovers links in many ways, uses them in different ways and completely ignores many links.

You have no way of knowing. Period. :)

Roger Montti

Of the tips that have not yet been offered, I can advise Index Status Checker (SE Ranking)

1. No tool can tell you whether Google has indexed a LINK and using it in the Link Graph.
2. No tool can tell you if a page has been indexed. That information is inside Google, period.
3. Google Search Console tells you if a page has been indexed for your own sites.
4. Site:Search does not tell the index status.

The google indexed pages checker is useful if you want to have an idea of how many of your web pages are being indexed by Google. It is important to perform this valuable indexing test because it can help you fix any issues on your pages so that Google will have them indexed and help you increase organic traffic.

<spam snip>

[edited by: not2easy at 11:28 am (utc) on Aug 28, 2022]
[edit reason] Please see TOS [webmasterworld.com] [/edit]

The question is not about checking indexed pages on your site. The question is about checking indexed links to your site. GSC is of no use for that.