Is the prayer valid if I ate sweets and did not wash my mouth before the prayer, given that ablution is already performed?

It is desirable for someone who stands for prayer to remove food remnants and their smell from their mouth with a siwak (tooth-cleaning twig). However, if they do not, their prayer is still valid. The Prophet, peace and blessings be upon him, prayed after eating meat and drinking milk without rinsing his mouth or performing ablution. Rinsing the mouth from the effects of food is desirable, not obligatory, unless the food eaten was camel meat, in which case ablution becomes obligatory as it nullifies ablution.