I have a transit flight to Los angeles and layover of 5 hrs in Guangzhou Airport.

Oh, as I know, there is no special indian food restaurant in the airport.
But don't worry. There are several Chinese traditional food restaurants that provide some vegetable dishes. You can go and taste.
In addition, there are many duty-free shops. You can buy some interesting and characteristic souvenirs. Or you can go to coffee shops. Listen some music and relax yourself. :-)

Thanks Anita , I really appreciate your time and efforts in replying me my query.