It was noon Wednesday, a few hours before Steny Hoyer would officially announced that he was joining Acting Gov. Blair Lee III's ticket as a candidate for lieutenant governor of Maryland. The scene was a banquet room at the Ramada Inn near Rte. 450 and the Capital Beltway.

Hoyer was moving briskly from table to table, shaking hands, occasionally letting loose with a piercing laugh. He was among friends - his fellow Democratic politicans from Prince George's County.

Winfield Kelly, the county executive, was off by himself in a corner of the room, observing Hoyer's every move.

"He looks vigorous and strong," said Kelly. 'He looks recharged, doesn't he?"

Then, his voice dropping in a twistful tone, Kelly added: It's his time . . . his time."

For the last four years, Hoyer and Kelly have carried equal prestige as the two most powerful elected officials in the most populous county in the state; Hoyer as president of the state Senate, Kelly as leader of the county government.

The two men have different backgrounds, different constituencies. But they share relative youth (Hoyer is 38; Kelly 42), remarkable energy and intense political ambitions. They both would like to be the governor of Maryland some day.

Two years ago, when Maryland politicians began thinking seriously about the next governor's race, Hoyer and Kelly reached an informal agreement that 1978 would be Hoyer's year. 'He had been in the vineyards longer," said Kelly. Steny deserved the first shot."

Kelly said he gave Hoyer his personal opinion back then that Hoyer might be better off retaining his Senate leadership position this year than running an uphill race for governor. But when Hoyer decided to make the race, Kelly gave him his full backing.

There were several times during the last year when gubernatorial candidates from other parts of the state - including Baltimore County Executive Theodore Venetoulis - approached Kelly and asked him to join their tickets as a candidate for lieutenant governor.

"I was flattered," said Kelly. "But they knew I would turn them down. There was no way I could run on a slate against Steny. My time will come."

This week, when Hoyer dropped back to a second spot on Lee's ticket, Kelly realized that his time" will probably come a little later than he had hoped, as late as 1994 if Lee, and then Hoyer, serve two terms as governor. Even if Lee serves only one term and grooms Hoyer as his successor, Kelly would have to wait more than a decade to get his shot.

No one expects Kelly to stay in the county executive's seat that long, but there are not many other places for him to go. Kelly considers himself a nuts-and-bolts administrator, not a legislator, and has said he is not particularly interested in running for Congress or U.S. Senate.

"This is going to knock my long-range timing out of kilter for a few years, but I'm not an old man," said Kelly. "Something will probably happen unexpectedly, the way it always does in politics. Steny might go for the U.S. Senate himself some day soon."

Although Hoyer and Kelly have rarely argued publicly, their relationship has never been extremely close. Many of Kelly's associates say the county executive is politically uncomfortable with Hoyer's closest ally, attorney Peter O'Malley, who is credited with putting together the dominant Democratic party organization in Prince George's.

His friends said Kelly was "hurt" by the fact that Hoyer did not include him among the handful of people who were informed of Hoyer's decision to join the Lee slate before the public announcement.

Kelly said that did not bother him. "I was with Steny Tuesday (the day before the announcement)," he said. "And I think he really wanted to tell me. I just didn't ask."