mysql 经纬度范围查询排序优化

1　　　　　　var req = new
2            {
3                //经度
4                Longitude = 1,
5                //纬度
6                Latitude = 1,
7                //跳过条数
8                offset = 1,
9                //显示条数
10                limit = 1,
11                //条件范围  每增加1搜索范围差不多增加110km
12                scope = 10,
13            };
14            
15            string sql = $@"select * from store where 1=1 ";
16            sql = sql + $@"and longitude > ({req.Longitude}-{ req.scope}) 
17                                and longitude < ({req.Longitude}+{ req.scope})
18                                and latitude > ({req.Latitude}-{ req.scope})
19                                and latitude< ({req.Latitude}+{ req.scope})
20                                order by ACOS(SIN(({req.Latitude} * 3.1415) / 180 ) *SIN((latitude * 3.1415) / 180 ) +COS(({req.Latitude} * 3.1415) / 180 ) * 
21                                COS((latitude * 3.1415) / 180 ) *COS(({req.Longitude}* 3.1415) / 180 - (longitude * 3.1415) / 180 ) ) * 6380 ";
22            sql = sql + ($@" limit { req.offset},{ req.limit}");