Springer Nature has made it free for its own conferences here:

http://scigraph-indexing-checks.springernature.com/

For others, you can search in publons: https://publons.com/publon/?order_by=date

If the title appears and you see a button named VIEW FULL BIBLIOGRAPHIC RECORD upon opening the record,

the manuscript must be indexed in CPCI. You can click the button to find the more details about WoS indexing.