clojure-search-spec-map

(defn findMapWithKey
    [targetCollection targetKey targetValue]
    (reduce-kv
      (fn [mapV keyV valueV]
        (if (map? valueV)
          (reduce-kv
            (fn [mapVunder keyVunder valueVunder]
              (if (and (= keyVunder targetKey) (= (get valueV keyVunder) targetValue)) valueV mapVunder))
            {}
            valueV
          )
        mapV)
      )
      {}
      targetCollection
    )
)

(def ex1 {:key1 "a" :key2 "b" :key3 {:underKey1 "a2" :underKey2 "b2"}})
(println (findMapWithKey ex1 :underKey1 "a2"))
(def ex1 {:key1 "a" :key2 {:underKey3 "a2" :underKey4 {:underKey5 "a2" :underKey6 "b2"}} :key3 {:underKey1 "a2" :underKey2 "b2"}})
(println (findMapWithKey ex1 :underKey1 "a2"))