Lol I had same issue ..use this trick.
Just lightly long touch or long press a,s or keys tht are not working..(not hardy)..then u will see it will work.
In my case I long press(lightly) key 's'.
And it works like ..=ssssssssssssssssss.
Then my all other keys also start working.
Just try 3,4 times it's will work have patience.(before doing this u can also use hair drier without temperature from safe distance to clean dust in keyboard).