SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3e39cc7e82f41bf624b7705e8ffb365132dc53e06b8b2d42aca6609abf44aca4' 
  AND token = 'zSi+2B934SzD2dcZ/g2aviuCMRNJgn8WlB/S08D1n4c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

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