What are the current updates for entering Thailand on a Student Visa during the lockdown?

If you were already issued a single entry 90 day Non-ED visa from a thai consulate you will see on it the "valid until" or "enter before" date.

You have that long to get IN to the country. If you don't get here before the visa expires you will need to get another one.

There is no provision to extend the validity of visas, you have to get IN to the country before it expires.