refactor get_ready_deposits query and index to hopefully make query faster

src/exchangedb/exchange-0001.sql

@@ -418,11 +418,12 @@ COMMENT ON INDEX deposits_coin_pub_merchant_contract_index
 CREATE INDEX IF NOT EXISTS deposits_get_ready_index
   ON deposits
   (shard
-  ,tiny
-  ,done
-  ,extension_blocked
   ,wire_deadline
   ,refund_deadline
+  ,tiny
+  ,done
+  ,kyc_ok
+  ,extension_blocked
   );
 COMMENT ON INDEX deposits_coin_pub_merchant_contract_index
   IS 'for deposits_get_ready';

src/exchangedb/plugin_exchangedb_postgres.c

@@ -1105,11 +1105,11 @@ prepare_statements (struct PostgresClosure *pg)
       " WHERE "
       "       shard >= $2"
       "   AND shard <= $3"
+      "   AND wire_deadline<=$1"
+      "   AND refund_deadline<$1"
       "   AND tiny=FALSE"
       "   AND done=FALSE"
       "   AND (kyc_ok OR $4)"
-      "   AND wire_deadline<=$1"
-      "   AND refund_deadline<$1"
       " ORDER BY "
       "   shard ASC"
       "  ,wire_deadline ASC"