Why date index is not used

Why Postgres 8.1 does not use makse_kuupaev_idx index in the following query
?

How to speed this query up ?

explain analyze select * from makse order by kuupaev desc, kellaaeg desc
limit 100

"Limit  (cost=62907.94..62908.19 rows=100 width=876) (actual
time=33699.551..33701.001 rows=100 loops=1)"
"  ->  Sort  (cost=62907.94..63040.49 rows=53022 width=876) (actual
time=33699.534..33700.129 rows=100 loops=1)"
"        Sort Key: kuupaev, kellaaeg"
"        ->  Seq Scan on makse  (cost=0.00..2717.22 rows=53022 width=876)
(actual time=0.020..308.502 rows=53028 loops=1)"
"Total runtime: 37857.177 ms"


CREATE TABLE makse(
  kuupaev date,
  kellaaeg char(6) NOT NULL DEFAULT ''::bpchar,
  guid char(36) NOT NULL,
  CONSTRAINT makse_pkey PRIMARY KEY (guid) )


CREATE INDEX makse_kuupaev_idx  ON makse  USING btree  (kuupaev);


Andrus.