Folding the river for one bet with top pair...

[tansoku]

Not counting KTos in villains range, and giving the other top 30% of hands..
Board: 3s 2h Ks 5c 7d
Dead:

equity (%) win (%) tie (%)
Hand 1: 39.4377 % 30.14% 09.30% { KdQs }
Hand 2: 53.4448 % 44.15% 09.30% { KK+, AKs, KTs+, AKo, KJo+ }
Hand 3: 07.1175 % 06.69% 00.43% { 55+, A2s+, K5s+, Q7s+, J8s+, T8s+, 98s, A7o+, A5o, K9o+, Q9o+, J9o+, T9o }

If you assume the other guy was on a FD and will fold:
Board: 3s 2h Ks 5c 7d
Dead:

equity (%) win (%) tie (%)
Hand 1: 41.9355 % 32.26% 09.68% { KdQs }
Hand 2: 58.0645 % 48.39% 09.68% { KK+, AKs, KTs+, AKo, KJo+ }

Getting 19:1 this is a must call.