#!/usr/bin/env python

def is_concealed(n):
    digits = str(n)
    template = "1_2_3_4_5_6_7_8_9_0"

    if len(digits) != len(template):
        return False

    return all(digits[i] == template[i] for i in range(0, len(digits), 2))

def main():
    print(next((n for n in range(1000000000, 1390000000, 10)
        if (n % 100 == 30 or n % 100 == 70) and is_concealed(n*n))))

if __name__ == "__main__": main()

$ time python3 concealed.py
real   0m21.866s
user   0m21.857s
sys    0m0.008s