Speed trumps all, besides the first couple luck points to override bad daily luck or to give the first boost (since it scales linearly off of a set value dependent on daily luck the first few matter a lot more)
If you're being smart with the way you're descending, that speed is going to matter a whole lot more when it comes to saving time
Not only that, but luck heavily falls off once you're able to reliably use staircases for annoying floors or just to skip down X amount of floors from the get go.
You're also able to get spicy eel continuously from within the cavern, it's super easy to get in bulk with trading ruby, and it's a useful speed buff everywhere, not just in the mines, so you don't always have to rearrange the inventory before and after a mining run.
That being said, if you're going to treasure rooms and don't have a magic rock candy (though you should, the extra luck and speed is absolutely worth it), lucky lunch is still a viable choice, especially if you're cooking it with qi seasoning as then the difference of one luck point is easier to overlook.
I'd say that ever since MRC was added, lucky lunch fell into a weird spot where you can get it faster than MRC, but you get the recipe so so so late naturally, and it's not even a buff you need to use often, so your 1 MRC a week is plenty enough.
At least with 1.6 you can get the recipe faster, albeit at quite the pretty dollar