Actual query:
SELECT SQL_NO_CACHE country_abbreviation, country_name, region, city, isp, latitude, longitude FROM ip2location WHERE ip_first <= 3335238065 AND ip_last >= 3335238065; 4.6 seconds

Profile:
Status	Time
(initialization)	0.000004
checking query cache for query	0.000073
Opening tables	0.000014
System lock	0.000022
Table lock	0.00001
init	0.000032
optimizing	0.000015
statistics	0.000213
preparing	0.000131
executing	0.000011
Sending data	4.651696 <--- What? it's 1 record
end	0.000047
query end	0.000008
freeing items	0.000019
closing tables	0.000011
logging slow query	0.000004

Explain:
1	SIMPLE	ip2location	range	PRIMARY,ip_last,ip_first	PRIMARY	4	NULL	1886656	Using where

Research:
SELECT SQL_NO_CACHE ip_first FROM ip2location WHERE ip_last >= 3335238065; .0007 seconds
SELECT SQL_NO_CACHE ip_last FROM ip2location WHERE ip_first <= 3335238065; .0007 seconds
SELECT SQL_NO_CACHE count(ip_last) FROM ip2location WHERE ip_first <=3335238065; 2,251,823 rows (1.3 seconds)
SELECT SQL_NO_CACHE count(ip_first) FROM ip2location WHERE ip_last >= 3335238065; 1,406,113 rows (.65 seconds)
SELECT SQL_NO_CACHE max(ip_first) AS first_max FROM ip2location WHERE ip_last >= 3335238065; 4278190080 (1 second)
SELECT SQL_NO_CACHE min(ip_first) AS first_min FROM ip2location WHERE ip_last >= 3335238065; 3335237632 (.69 seconds)
SELECT SQL_NO_CACHE max(ip_last) AS last_max FROM ip2location WHERE ip_first <= 3335238065; 3335239167 (1.4 seconds)
SELECT SQL_NO_CACHE min(ip_last) AS last_min FROM ip2location WHERE ip_first <= 3335238065; 33996343 (1.37 seconds)

...
WHERE
  ip_first >= 123456
ORDER
  BY
    ip_first DESC
LIMIT 1;