De Bruyne has won six Premier League titles among 13 major trophies since joining City in 2015, a year before Guardiola's arrival.
The 33-year-old is out of contract at the end of the season and has previously hinted he could be tempted by the riches on offer in the Saudi Pro League.
"I would like to have a 23 year-old Kevin and sign a contract for 10 more years," Guardiola said on Friday.
"There are players that impact the legacy of this club and will be there forever.
"It’s not easy (to replace), but in the moment it’s going to happen we’ll see."
De Bruyne was instrumental to City snapping a seven-game winless run by beating Nottingham Forest 3-0 on Wednesday in his first start for nearly three months.
Guardiola has been cautiously managing the playmaker's minutes but conceded he may be pressed into selecting De Bruyne again for Saturday's trip to Crystal Palace due to an injury crisis.
"We don't have many players so we'll see," added Guardiola.
"Important (to have him) back but after a long time. (Now we play) three days, three days, three days, we'll see how does he react to this amount of games."
Phil Foden remains out due to illness, while Nathan Ake is sidelined by a muscle injury late on against Forest.
Rodri, John Stones, Mateo Kovacic and Oscar Bobb are also missing for the English champions.
