求解决分钟级数据查询慢--区间查询

现在我遇到一个mysql数据查询时间太慢问题 数据结构为一对多 数据查询出来全部返回不需要使用分页
描述如下：
前端要求通过时间区间查询一个月甚至几个月的分钟级数据(分钟数据：一分钟一条)，并在折线图展示，但是我后台sql查询很慢(使用的嵌套子查询，字段已建立索引，并强制走了索引)

<!--分钟数据主表-->
    <resultMap type="com.arid.dataDisplay.domain.MinuteDataRecord" id="MinuteDataRecordResult">
        <result property="id" column="id"/>
        <result property="stationCode" column="station_code"/>
        <result property="aqi" column="aqi"/>
        <result property="primaryPollutant" column="primary_pollutant"/>
        <result property="exceedPollutant" column="exceed_pollutant"/>
        <result property="sampleTime" column="sample_time"/>
        <result property="createTime" column="create_time"/>
        <collection property="mpList" ofType="com.arid.dataDisplay.domain.MinutePollutantDataVO"
                    javaType="java.util.List" select="selectPollutantData"
                    column="id" />
    </resultMap>

    <!--分钟数据副表-->
    <resultMap type="com.arid.dataDisplay.domain.MinutePollutantDataVO" id="MinutePollutantDataResult">
        <result property="spdc_id" column="id"/>
        <result property="recordId" column="record_id"/>
        <result property="pollutantCode" column="pollutant_code"/>
        <result property="pollutantName" column="pollutant_name"/>
        <result property="dataValue" column="data_value"/>
        <result property="flag" column="flag"/>
        <result property="iAqi" column="i_aqi"/>
        <result property="pollutionLevel" column="pollution_level"/>
        <result property="spdc_sample_time" column="sample_time"/>
    </resultMap>

<select id="selectMinuteDataRecordByCodeAndTime" parameterType="String" resultMap="MinuteDataRecordResult" fetchSize="10000">
        select
            sdrc.id,
            sdrc.exceed_pollutant,
            sdrc.primary_pollutant,
            sdrc.sample_time,
            st.station_name,
            st.latitude,
            st.longitude
        from minute_data_record sdrc
        FORCE INDEX(`id`)
        left join  station AS st
        on st.station_code = sdrc.station_code
        <where>
            <if test="code!=null and code!=''">
                AND  sdrc.station_code = #{code}
            </if>
            <if test="startTime!=null and startTime!=''">
                AND
                <![CDATA[
                  sdrc.sample_time >= #{startTime,jdbcType=TIMESTAMP}
                ]]>
            </if>
            <if test="endTime!=null and endTime!=''">
                AND
                <![CDATA[
                  sdrc.sample_time <= #{endTime,jdbcType=TIMESTAMP}
                ]]>
            </if>
        </where>
    </select>

<select id="selectPollutantData" parameterType="map" resultMap="MinutePollutantDataResult">
       SELECT
        spdc.id AS spdc_id,
        spdc.record_id,
        spdc.pollutant_code,
        spdc.pollutant_name,
        spdc.data_value,
        spdc.sample_time,
        spdc.i_aqi
      FROM
        minute_pollutant_data spdc
        FORCE INDEX(`record_id`)
      where  spdc.record_id=#{id}
    </select>

怎么优化