Need help on a troublesome query plan

On PostgreSQL Version 7.2.1 on Redhat Linux 7.1

Table bld_tb_bus_fact definition
================================

Column | Type | Modifiers
-----------------+-------------------------- +-----------
bus_fact_id | bigint | not null
bus_fact_ts | timestamp with time zone | not null
party_id | bigint |
svc_id | bigint | not null
bus_fact_data | text | not null
bus_fact_typ_cd | character(10) | not null
bus_fact_kywrd | character varying(300) |
cont_id | bigint |
perfby_id | bigint |

Index "bld_x1_tb_bus_fact"
Column | Type
-----------------+---------------
party_id | bigint
bus_fact_typ_cd | character(10)
cont_id | bigint
btree

With the following query on 50000 records:

explain
SELECT bld_TB_BUS_FACT.BUS_FACT_ID AS id
FROM bld_TB_BUS_FACT
WHERE bld_TB_BUS_FACT.PARTY_ID=1320677
AND bld_TB_BUS_FACT.BUS_FACT_TYP_CD='MSG_SENT'
AND bld_TB_BUS_FACT.CONT_ID=786448
AND bld_TB_BUS_FACT.BUS_FACT_KYWRD ILIKE '%MT-ID=3407979%'
AND bld_TB_BUS_FACT.BUS_FACT_KYWRD ILIKE '%S-ID=1310723%'
limit 1;

psql:test.sql:9: NOTICE: QUERY PLAN:

Limit (cost=0.00..2264.16 rows=1 width=8)
-> Seq Scan on bld_tb_bus_fact (cost=0.00..2264.16 rows=1 width=8)

EXPLAIN

I don't understand why it's not using the defined index, even after performing VACUUM FULL ANALYZE on the table.
I tried disabling seqscan but that didn't change anything.

I'm open to suggestions anyone

Thanks!

----------------------------------------------------------------------------------------
Alain Lavigne - Data Administrator - ZAQ Interactive Solutions E-Mail: alavigne(at)zaq(dot)com
297 St-Paul, West - Montreal, Quebec, Canada - H2Y 2A5
Phone: 514-282-7073 ext: 371 - Fax: 514-282-8011