Why is MES Future Index different than SPX?

Hi Guys,

I'm still learning futures.

So I want to buy a MES 1 Contract Expiring March 25th. The SPX closed this year at 5881.83. Right now the MES Contract is selling at 5950. I'm confused why is it not selling near 5881.83?

Like are you paying $50+ dollars for the premium? None of this make sense?

Also isn't it better to buy when market open. Since I'm assuming premium will go down and trade closer to the index.

If not, what strategy work the best?