that's a sub-sub-key, so osquery has no way to reflect having traversed the plist to get at the boolean value in question - in plistBuddy syntax (because defaults can only populate the whole sub-tree) it's at

/usr/libexec/PlistBuddy -c "print :Accounts:0:Services:2:Enabled" ~/Library/Preferences/MobileMeAccounts.plist