I’m particularly interested in using of variables VAR_trip_time and VAR_cmimi from the first query
and then reuse those values in other queries below. the first code is how my query is, the second part is what i think to do .

BEGIN
DECLARE PRICE_val INT;
DECLARE trip_time_val INT;

UPDATE sku_rides R
INNER JOIN sku S ON S.skuID = R.skuID
SET R.endTime = NOW(), 
    R.zona = S.zona,
    R.price = ROUND(TIMESTAMPDIFF(SECOND, R.startTime, NOW()) * price_per_1_sec),
    R.trip_time = TIMESTAMPDIFF(SECOND, R.startTime, NOW())
WHERE R.skuID = skuID AND R.userID = userID AND R.endTime IS NULL  ORDER BY rideID DESC LIMIT 1;


SELECT price INTO PRICE_val FROM sku_rides WHERE skuID = skuID AND userID = userID ORDER BY rideID DESC LIMIT 1;

UPDATE users SET kredit = kredit - PRICE_val WHERE userID = userID;

UPDATE sku SET userID = NULL WHERE skuID = skuID;

-- RETURN 1; // No need for RETURN statement in a procedure
END

i tried this

BEGIN
    DECLARE VAR_trip_time INT;
    DECLARE VAR_cmimi INT;

    UPDATE sku_rides R
    INNER JOIN sku S ON S.skuID = R.skuID
    SET R.endTime = NOW(), 
        R.zona = S.zona,
        VAR_trip_time = TIMESTAMPDIFF(SECOND, R.startTime, NOW()),
        VAR_cmimi = ROUND(VAR_trip_time * cmimi_per_1_sekond),
        R.cmimi = VAR_cmimi,
        R.trip_time = VAR_trip_time
    WHERE R.skuID = skuID AND R.userID = userID AND R.endTime IS NULL 
    ORDER BY rideID DESC 
    LIMIT 1;

    UPDATE users SET kredit = kredit - VAR_cmimi WHERE userID = userID;

    UPDATE sku SET userID = NULL WHERE skuID = skuID;

    -- RETURN 1; // No need for RETURN statement in a procedure
END