Difference between using COUNT in column and COUNT with "*"

Question

I accomplished 2 querys in a bank where I needed to know the amount of records based on a column but if I change the parameter of COUNT() the results are different.

SELECT COUNT(`time`) as 'tempo' 
from db.table 
WHERE `time` <= 3000 
AND (`created_at` BETWEEN DATE_SUB(CURDATE(), INTERVAL 1 DAY) AND NOW();
// A coluna `time` é do tipo "float" e armazena valores do tipo: 1.000, 0.985, 32.000

SELECT COUNT(*) as 'tempo' 
from db.table 
WHERE `time` <= 3000 
AND (`created_at` BETWEEN DATE_SUB(CURDATE(), INTERVAL 1 DAY) AND NOW();

What’s between using with * and with the column name?