Pretinaverse

You know, unlocking bootloader is only neccesary if you are planning to install a custom recovery. And a custom recovery, like twrp, only is needed if you want to install a custom rom or if you want to install the root via recovery. BUT, if you're lucky, you don't need any of that to root your phone. You can try some apps like KingRoot or Kingo Root. Give it a try. Who knows, maybe you are lucky