Super fast pickaxe with no drops

If you want a fast pickaxe:

/give @p minecraft:diamond_pickaxe{Unbreakable:1,ench:[{id:32,lvl:100}]} 1   

This pickaxe will instantly mine in survival mode. It will drop blocks so you can use
/gamerule doTileDrops false as commented by Fabian to prevent blocks from dropping as you clear an area.

If you don't care about the pickaxe and just want to clear an area for yourself, you can use the fill command:

/fill ~-1 ~ ~-1 ~1 ~2 ~1 minecraft:air replace

This will clear a 3x3x3 area around you but keep the ground level with your feet. You would have to type it in each time you wanted to use it. You would expand the coordinates to clear a larger area.

You can put a similar command into a Repeat Unconditional Always Active command block:

execute at <playerName> run fill ~-1 ~ ~-1 ~1 ~2 ~1 minecraft:air replace

This would constantly clear an area around you as you walk around. Don't stand to close to the command block while setting it up or you will clear the command block.

Note: These commands were tested in 1.13 snapshot 18w19a. They function properly. I did have a weird visual glitch when holding any enchanted item.