MongoDB $geoWithin query very slow - mongodb

Question

I have a huge collection of documents (~1 milion), each doc is quite big (avgObjSize: 13268). Each document has a geo point:
Accomodation:
{
"location" : {
[...]
"geoLocation" : {
"type" : "Point",
"coordinates" : [
-42.61343486,
71.70936503
]
}
}
}
I have the following index:
{
"location.geoLocation" : "2dsphere"
}
I do this simple query (it should keep a 85km radius):
db.getCollection('Accomodation').find({
"location.geoLocation" : {
"$geoWithin" : {
"$centerSphere" : [
[
2.34682537615297,
48.8536252472747
],
0.0131543876703093
]
}
}})).limit(100)
the query execution takes from 1 to 6 seconds, and I think it's slow.
Even if the server is not powerfull it should take so much less time to get 100 docs, it seems it uses the index, so the docs in the area should not even be fetched for the scan.
What am I missing?
This is the query stats
{
"queryPlanner" : {
"plannerVersion" : 1,
"namespace" : "Stage-BluePillow.Accomodation",
"indexFilterSet" : false,
"parsedQuery" : {
"location.geoLocation" : {
"$geoWithin" : {
"$centerSphere" : [
[
2.34682537615297,
48.8536252472747
],
0.0131543876703093
]
}
}
},
"winningPlan" : {
"stage" : "LIMIT",
"limitAmount" : 100,
"inputStage" : {
"stage" : "FETCH",
"filter" : {
"location.geoLocation" : {
"$geoWithin" : {
"$centerSphere" : [
[
2.34682537615297,
48.8536252472747
],
0.0131543876703093
]
}
}
},
"inputStage" : {
"stage" : "IXSCAN",
"keyPattern" : {
"location.geoLocation" : "2dsphere"
},
"indexName" : "location.geoLocation_2dsphere",
"isMultiKey" : false,
"isUnique" : false,
"isSparse" : false,
"isPartial" : false,
"indexVersion" : 1,
"direction" : "forward",
"indexBounds" : {
"location.geoLocation" : [
"[5116089176692883456, 5116089176692883456]",
"[5170132372221329408, 5170132372221329408]",
[...]
"[5183361696126730241, 5183502433615085567]",
"[5183643171103440896, 5183643171103440896]"
]
}
}
}
},
"executionStats" : {
"executionSuccess" : true,
"nReturned" : 100,
"executionTimeMillis" : 1399,
"totalKeysExamined" : 151,
"totalDocsExamined" : 142,
"executionStages" : {
"stage" : "LIMIT",
"nReturned" : 100,
"executionTimeMillisEstimate" : 1180,
"works" : 152,
"advanced" : 100,
"needTime" : 51,
"needYield" : 0,
"saveState" : 35,
"restoreState" : 35,
"isEOF" : 1,
"invalidates" : 0,
"limitAmount" : 100,
"inputStage" : {
"stage" : "FETCH",
"filter" : {
"location.geoLocation" : {
"$geoWithin" : {
"$centerSphere" : [
[
2.34682537615297,
48.8536252472747
],
0.0131543876703093
]
}
}
},
"nReturned" : 100,
"executionTimeMillisEstimate" : 1180,
"works" : 151,
"advanced" : 100,
"needTime" : 51,
"needYield" : 0,
"saveState" : 35,
"restoreState" : 35,
"isEOF" : 0,
"invalidates" : 0,
"docsExamined" : 142,
"alreadyHasObj" : 0,
"inputStage" : {
"stage" : "IXSCAN",
"nReturned" : 142,
"executionTimeMillisEstimate" : 40,
"works" : 151,
"advanced" : 142,
"needTime" : 9,
"needYield" : 0,
"saveState" : 35,
"restoreState" : 35,
"isEOF" : 0,
"invalidates" : 0,
"keyPattern" : {
"location.geoLocation" : "2dsphere"
},
"indexName" : "location.geoLocation_2dsphere",
"isMultiKey" : false,
"isUnique" : false,
"isSparse" : false,
"isPartial" : false,
"indexVersion" : 1,
"direction" : "forward",
"indexBounds" : {
"location.geoLocation" : [
"[5116089176692883456, 5116089176692883456]",
"[5170132372221329408, 5170132372221329408]",
[...]
"[5183361696126730241, 5183502433615085567]",
"[5183643171103440896, 5183643171103440896]"
]
},
"keysExamined" : 151,
"dupsTested" : 0,
"dupsDropped" : 0,
"seenInvalidated" : 0
}
}
}
},
"serverInfo" : {
"host" : "metasearch",
"port" : 27017,
"version" : "3.2.10",
"gitVersion" : "79d9b3ab5ce20f51c272b4411202710a082d0317"
},
"ok" : 1.0
}