[{"_id":"xAFG6f8wQR_xw5vk1s","users":["xAFG6f8wQR","xw5vk1s"],"like":true}]

db.collection.aggregate([{$addFields:{secondItem:{$arrayElemAt:["$users",1]}}},{$match:{$and:[{users:{$in:["$users","xw5vk1s"]}},{$expr:{$eq:["$secondItem","xw5vk1s"]}}]}}])