What is the highest Rank of Karen Pickering when she had a time of less than 55.71?
CREATE TABLE "semifinal_2" (
  "rank" real,
  "lane" real,
  "name" text,
  "nationality" text,
  "time" real
);
SELECT MAX("rank") FROM "semifinal_2" WHERE "name"='karen pickering' AND "time"<55.71;