See the TS-EAMCET FAQ section states that the EWS certificate will be required during the counselling. But there are no date specified. Now as per most other examination I would recommend you that you should have a EWS certificate issued in the Fiscal year 2021-22 i.e., after 31st of March,2021.

TO know more about TS EAMCET visit the link below:

https://engineering.careers360.com/articles/ts-eamcet-latest-news-and-updates

I hope this answer helps. All the very best for your future endeavors!