@baris Sorry. My fault. I forgot to select the NodeBB database 
See below
db.objects.findOne({_key: "blog-comments"});
{
"_id" : ObjectId("619b94d1bd1e82aef790fb9e"),
"_key" : "blog-comments",
"61768dda84686c09dddd1ef2" : 132,
"6176a31a84686c09dddd1f0d" : 133,
"6179569c84686c09dddd1fa7" : 134,
"6176d2ca84686c09dddd1f95" : 135,
"6176d21884686c09dddd1f88" : 136,
"6176c0f684686c09dddd1f73" : 137,
"6176bd7e84686c09dddd1f59" : 138,
"6176b78f84686c09dddd1f22" : 139,
"61768e6f84686c09dddd1efa" : 140,
"61768ad984686c09dddd1eea" : 141,
"617689a484686c09dddd1ebf" : 142,
"6176893584686c09dddd1eb6" : 143,
"6176873384686c09dddd1eae" : 144,
"61a8ac37c2aaf679e63d3336" : 152,
"61a8add7c2aaf679e63d3346" : 153,
"61a8b08ac2aaf679e63d335d" : 154,
"61a8b14fc2aaf679e63d336b" : 155,
"61a8b842c2aaf679e63d337b" : 156,
"61a8cd79c2aaf679e63d338e" : 157,
"61a8d13ac2aaf679e63d339d" : 158,
"61a8d1bec2aaf679e63d33ac" : 159,
"61a8d29bc2aaf679e63d33c6" : 160,
"61a8d318c2aaf679e63d33da" : 161,
"61b35c493606679963e1d2fb" : 167,
"61b38b413606679963e1d30b" : 168,
"61b3a0e93606679963e1d38c" : 169,
"61b3a1fe3606679963e1d3a0" : 170,
"61b3a40d3606679963e1d3b0" : 171
}