Database
[{_id:ObjectId("65fee1b40839f1f886ee94a9"),val:"9"},{_id:ObjectId("65fee1b40839f1f886ee94aa"),val:"a"},{_id:ObjectId("65fee1b40839f1f886ee94ab"),val:"b"}]
Query
db.collection.find({$expr:{$eq:["$_id",{$toObjectId:"65fee1b40839f1f886ee94a9"}]}})