Lua resetting storage after 24 hours

[Kahras]

local function getExpForLevel(level)
    level = level - 1
    return ((50 * level * level * level) - (150 * level * level) + (400 * level)) / 3
end


local keywordHandler = KeywordHandler:new()
local npcHandler = NpcHandler:new(keywordHandler)
local talkState = {}
function onCreatureAppear(cid)                npcHandler:onCreatureAppear(cid)             end
function onCreatureDisappear(cid)             npcHandler:onCreatureDisappear(cid)         end
function onCreatureSay(cid, type, msg)         npcHandler:onCreatureSay(cid, type, msg)     end
function onThink()                             npcHandler:onThink()                         end


function creatureSayCallback(cid, type, msg)
    if(not npcHandler:isFocused(cid)) then
        return false
    end
        local creature = Player(cid)
        local npc = Npc(getNpcCid())

    if msg:lower() == "task" then
        if getPlayerStorageValue(cid, 31250) <= 0 then
            if getPlayerStorageValue(cid, 31252) <= os.time() then        -- sprawdza czy gracz odczekal 24h
                local tasks_ = {}
                local n = 0
                for k, v in pairs(tasks) do
                    n = n+1
                    if getPlayerLevel(cid) >= tasks[n].lvRange[1] and getPlayerLevel(cid) <= tasks[n].lvRange[2] then
                        table.insert(tasks_, {tasks[n], n})
                    end
                end
            if getPlayerStorageValue(cid, 31254) < 2 then
                if #tasks_ > 0 then
                    taskx[cid] = tasks_[math.random(1, #tasks_)]
                    selfSay("To twoja "..getPlayerStorageValue(cid, 31254).." misja. Musisz zabic "..taskx[cid][1].amount.." "..taskx[cid][1].name.."! Wroc gdy to zrobisz.", cid)
                    local task = taskx[cid][1]
                    setPlayerStorageValue(cid, 31250, taskx[cid][2])
                    setPlayerStorageValue(cid, 31251, 0)
                    doSendMagicEffect(getPlayerPosition(cid), 13)   
                else
                    selfSay("Sorry ale nie mam dla Ciebie zadan.", cid)
                end
            end
            else
                selfSay("Sorry ale taski mozesz robic co 24 godziny, przyjdz pozniej.", cid)            -- odpowi
            end
        else
            local task = tasks[getPlayerStorageValue(cid, 31250)]
            if task.amount <= getPlayerStorageValue(cid, 31251) then
                setPlayerStorageValue(cid, 31250, 0)
                setPlayerStorageValue(cid, 31251, 0)
                setPlayerStorageValue(cid, 31253, getPlayerStorageValue(cid, 31253) + task.points)
                doSendMagicEffect(getPlayerPosition(cid), 13)
                doSendMagicEffect(npc:getPosition(), CONST_ME_MAGIC_BLUE)
                creature:addExperience(getExpForLevel(creature:getLevel() + task.lvReward) - creature:getExperience(), false)
                selfSay("Brawo! Twoja nagroda to: "..task.lvReward.." lv oraz "..task.points.." task punktow.", cid)
                setPlayerStorageValue(cid, 31254, getPlayerStorageValue(cid, 31254) + 1)    -- BLOKADA MAX 2 TASKI
            if getPlayerStorageValue(cid, 31254) == 2 then
                setPlayerStorageValue(cid, 31252, os.time()+10) --dla testu 10 sekund
            end
            else
                selfSay("Jeszcze nie skonczyles zadania! Zostalo ci do zabicia "..task.amount-getPlayerStorageValue(cid, 31251).." "..task.name..".", cid)
            end
        end
    end   
    return true
end

npcHandler:setMessage(MESSAGE_GREET, "Witaj! |PLAYERNAME|! Moze mam dla Ciebie zadanie.. [task]")
npcHandler:setMessage(MESSAGE_FAREWELL, "Do zobaczenia!")
npcHandler:setCallback(CALLBACK_MESSAGE_DEFAULT, creatureSayCallback)
npcHandler:addModule(FocusModule:new())

Hello i have a problem edited this script.
I want the player to be able to complete 2 missions every 24 hours.
this is getPlayerStorageValue(cid, 31254) which saves how many missions the player has completed
And I have a problem with resetting 31254 storage after 24 hours.

Can someone help me achieve this?