Put a breaker bar on the crank pulley nut, if it turns initally without too much effort, plug it in and go with it -though I would think about priming the oil pump, as it could well have leaked down in 2 years...
I had a 957cc fiesta engine that got water in a plug hole whilst sitting under a bench, this clearly was not good for it, as it took a really good heave to get it to free up, no idea what it looked like inside, but it gave me another 10,000 miles before the car itself went for scrap, the engine was still going strong, albeit needing a topup every thousand miles, and a bit smokey on overrun... but the engine ran fine, even with the valves permanently dancing around on the bonnet