At least on 6.4.2 "restricting to search upto a time" and "restricting search to few index" can be achieved by defining roles and then adding this role to any user. Try below
Settings > Access controls » Roles » Add new
On this "Add New" page go to section: Search restrictions, second option: "Restrict search time range" which defines:
Set a maximum time window (in seconds) for searches for this role. For example, set this to '60' to restrict this role's searches to 1 minute before the most recent time specified in the search. You can also set this to '0' to explicitly make the window infinite, or '-1' to unset the window for this role (can be overridden by imported roles).
On the same add new role page go right to bottom to find "Indexes" section to restrict a role from viewing only few indexes.
Indexes
Restrict this role's searches to the specified index(es). Search results for this role will only show events from these indexes.
Once the role is defined, create a user and add this new role to the user. From here on the user will have access only to the indexes specified and will only be able to search in the time range specified on the role.
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