Surely mSATA is a 'keyed' connector - it just doesn't conform to the M.2 standard?
No, the mSATA connector is identical to that of mini PCIe (mPCIe) so both mSATA and mPCIe will fit into the slot, as there is no keying. However, mSATA and mPCIe are still two different protocols. Some of these slots are compatible with mSATA only. Some are compatible with mPCIe only. Some others are 'hybrid' so they are compatible with
both mSATA
and mPCIe. (None of these are compatible with M.2.) The notch in the slot only makes it impossible to insert the module backwards into the slot, and, the slot only has one notch. So, this notch doesn't provide any keying—very unlike the M.2 connector type.
That being said, the keying of M.2 doesn't make it impossible to insert a B+M Key SATA M.2 SSD into the type of M Key M.2 slot that is NVMe-only. Some M Key M.2 slots are hybrid so they are compatible with both NVMe and SATA M.2, but a lot of them are not. Either way, like I already said, it is impossible to insert a mSATA SSD into an M.2 slot.
I'd go with these enclosures:
For your mSATA drive (enclosure also supports nVME) NOTE! I did not check the physical dimensions of your drive.
Inateck - Hard Drive Enclosure / M.2 NVMe SATA SSD FE2024
Again, it is impossible to insert a mSATA SSD into an M.2 slot. Therefore, this won't work.
For your SATA drive:
Inateck SATA enclosure - FE2005
I have one of these and it is great.
or
Inateck SATA enclosure - FE2014
All the above are cheap, and often have great discounts and work like clockwork. I'm very happy with Inateck products.
The latter choice seems better. With the 1TB Samsung 950 PRO, just like the one from post #2, this one should allow up to ~15% faster read speed compared to a typical 5Gbps enclosure. Even though 15% isn't that huge, the price is why this one looks to be a bit of a no-brainer IMO still nevertheless.
However, no matter the fact that it is the 1TB version we're talking, the 950 PRO is still only an 11 year-old relic. I would definitely take a look at its S.M.A.R.T. values to get a handle on how much life it's got left before buying such an enclosure, as 2.5″ SATA drives are already nearly phased out.
Generally speaking, if you don't have a computer museum, these drives will soon no longer be worth trying to find suitable 2.5″ SATA replacements for them after they go belly up. The same also holds true about mSATA.