Mongols invaded Eastern and Central Europe several times, but they always turned back. There are at least two common explanation for that.
First, European countryside was infested with castles. Defeating the king and sacking his capital wasn't enough to pacify the land. Mongols would have had to deal with every local warlord separately, and Europe wasn't worth the trouble.
Second, Mongols were getting too far away from the steppe. Their armies could not stay in Europe in the long term due to the lack of large enough pastures.
The hills and forests of Western Europe were also unfavourable for their preferred cavalry based tactics. And even the damp weather was against them since they couldn’t use their compound bows in the rain.
First, European countryside was infested with castles. Defeating the king and sacking his capital wasn't enough to pacify the land. Mongols would have had to deal with every local warlord separately, and Europe wasn't worth the trouble.
Second, Mongols were getting too far away from the steppe. Their armies could not stay in Europe in the long term due to the lack of large enough pastures.