The phone being a new entrant, I could not find many options for the flip covers for your Asus Zenfone Go 4.5. A couple of them I could manage to find out are -
1. Asus ZenFone Go 4.5 Flip Cover Universal Flip Cover
This cover is available in white color variant. It comes with magnetic lock. Priced at Rs. 600 , you can buy it on latestone.com. The cover is also available in different color options of blue, brown, red and black.
2. Wow Premium Design Back Cover Case for Asus Zenfone 4.5
Available with multiple color and design options, you can buy the cover from Amazon India. It is priced at Rs. 399.
3. Noise Go Spikey Printed Cover
The cover is durable and long lasting. You can buy it on Amazon India. The cover can be bought at Rs. 299. You need to pay Rs. 45 extra towards shipping.