Minecraft is so laggy, even on super flat?

Turn the video settings to minimum, install optifine, simplified texture pack

if that doesn't work, its because your laptop is too old

First go to options and set particles to minimal.
Render distance or view field to tiny, and everything else to the lowest possible.
Don't ever expect for any game that is anything besides games with a 16 bit style to run smoothly on a laptop.

That very much includes minecraft.
Get a better, desktop computer or play on console i don't know.
Also, how old are you and what games besides minecraft if any do you like to play?