Distributing a single table across multiple disks of different performance?
How to put data on a different disk: (using tablespaces)

CREATE TABLESPACE fastspace LOCATION '/srv/fast_disk/postgresql/data';


https://www.postgresql.org/docs/10/static/manage-ag-tablespaces.html

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How to make two tables behave like one: (SQL inheritance)

CREATE TABLE TABLE_FAST () inherits TABLE_SLOW TABLESPACE fastspace;


You will also need to add constraints and indices as apropriate to this new table.

https://www.postgresql.org/docs/10/static/tutorial-inheritance.html

Now selects from TABLE_SLOW will also see the data in TABLE_FAST

you may also benefit from implementing constraint exclusion (also described on that page), but the index on Loaded_Time (which I am assuming you have) should give a good speed increase itself

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How to move data data: (CTE delete returning)

eg: 3 days old

with deleted as ( 
     delete from only TABLE_FAST 
     where Loaded_Time &lt; 'now()' - '3 days'::interval
     returning * )
insert into slow_table select * from deleted;