SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '15aba1cfb6e01fcb3527372b9d4fad01b180a715ce9f9e49553b0b7c83b408d4' 
  AND token = 'tmx1cJvLjQiC6jttnrkE6iGnDG/Zgd4P9BMiwlCXxE0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00012

Explain
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE Impossible WHERE noticed after reading const tables