PokerStars - $0.10 NL (6 max) - Holdem - 6 players
Hand converted by PokerTracker 4

UTG: 138.8 BB (VPIP: 50.00, PFR: 0.00, 3Bet Preflop: 0.00, Hands: 22)
MP: 275.4 BB
CO: 90.1 BB (VPIP: 63.83, PFR: 31.91, 3Bet Preflop: 26.09, Hands: 47)
BTN: 161 BB (VPIP: 21.81, PFR: 6.63, 3Bet Preflop: 2.96, Hands: 419)
SB: 135.8 BB (VPIP: 31.02, PFR: 17.97, 3Bet Preflop: 1.19, Hands: 8,739)
Hero (BB): 113.4 BB

SB posts SB 0.5 BB, Hero posts BB 1 BB

Pre Flop: (pot: 1.5 BB) Hero has 6 J

UTG calls 1 BB, fold, CO raises to 2 BB, fold, fold, Hero calls 1 BB, UTG calls 1 BB

Flop: (6.5 BB, 3 players) 4 K 5
Hero checks, UTG checks, CO checks

Turn: (6.5 BB, 3 players) 3
Hero bets 4.7 BB, UTG calls 4.7 BB, CO calls 4.7 BB

River: (20.6 BB, 3 players) 4
Hero bets 60 BB, V?, V?,

pre is ok with 2 fish
c/c a small turn bet or lead turn small
river is massive spew, if you want to fold out A high, bet small and hope they do

Fold Preflop.
You should be calling with a stronger range against these 2 villains.

Never Bluff a calling station.(UTG Villain)

Never Bluff a maniac.(CO Villain)

I don't like how you played this hand at all. Playing this hand the way you did against these types of players is just burning money.

What are we trying to fold out by overbetting here? A high?

pre is super standard, river sizing doesn't make sense, you can get the job done with a lot less.

When you get the bargain price pre-flop, you can call with a very wide/weak range. But then you don't have to "fight" for the pot with the weakest parts of your range. Based on the pot odds (assuming UTG calls), you only need to win this pot 15% of the time, but J6ss is not particularly high in your range (in terms of equity) on the turn, as you have some Kx, some 2prs, straights, and a lot of FDs.
That's not to say the turn bet is bad, but I wouldn't necessarily be going out of my way with this combo. A smaller river bet probably achieves more or less the same thing as overbetting on the river. When the river pairs the board, fish hate folding any pairs. Given that the flop checked through, it's also possible that it improved them to trips.