As you can see the CQI value is very high so you are close to the max data-rate.
CQI is not high at all for this level of signal (RSRP), it should have been 15. With CQI=12 you can not reach more than approx. 60% of LTE cell maximum throughput.
Better quantity to assess LTE signal quality is SINR (or RSRQ if SINR is not calculated). I've once found a (real life) chart with plotted cell throughput vs. SINR. It showed that with SINR=10, max achievable throughput was between 10 and 35 Mbps, so OP's result is not bad actually. To achieve high throughput (say more than 75% of cell capacity), SINR has to be better than 20.
Low SINR combined with high RSRP means that either there's strong interference on LTE signal (perhaps you were placed "in between" the LTE sectors, try to place yourself directly in front of one base station antenna) or, even more probably, you actually have too high LTE signal, which can overload Rx pre-amplifier of data card and induce noise inside the receiver (keep in mind that LTE terminals are capable of decent performance down to RSRP as low as -110 dBm!). Our tests showed that most of terminals (data cards and phones) had best performance when RSRP was lower than -60 dBm and higher than -70 dBm. With RSRP getting higher, performance dropped.
A side note: if both network and terminal support LTE-advanced modulation schemes (up to 256QAM in downlink and 64QAM in uplink), sector max downlink throughput increases by 30% and max uplink throughput increases by 50% compared to "legacy" LTE ... sector in question could, theoretically, offer up to 100Mbps in downlink (UL heavily depends on terminal). But to realize that speedup, SINR absolutely has to be over 20, possibly better than 25.
