[{
'name':name1
'date':''2019-07-07 15:22'
},
{
'name':name2
'date':''2019-07-07 15:23'
}]

 select count(distinct name) from t where date> date_sub(now(), interval 5 minute)

 t=[{
'name':"name1",
'date':3.14
},
{
'name':"name2",
'date':3.15
},
{
'name':"name3",
'date':3.16
},
]
print(len(set([i["name"] for i in t if i["date"]>=3.15])))
>>> 2