A very well balanced match of cpu and gpu.
The GTX1050ti will run on pcie slot power unless it is one of the highly overclocked versions that needs aux 6 pin power.
In theory, 300w will suffice.
But, I highly recommend over provisioning a psu.
It will allow for a stronger future graphics card upgrade.
It will run cooler, quieter, and more efficiently in the middle third of it's range.
A PSU will only use the wattage demanded of it, regardless of it's max capability.
Your cpu can run a card perhaps as strong as a GTX1070ti.
I suggest at least a good 550w psu.
You may pay a bit more but will not go wrong with a 550w Seasonic focus.
rated 9.8/10 by jonnyguru.
https://www.newegg.com/Product/Product.aspx?item=N82E16817151189
Seasonic usually has sales this time of year, so do some shopping.