SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ab6547c671ff131ecbb56b903c4c58c64e185f143e1e6ebb0030d12ce17ce51f' 
  AND token = 'oEuq5li3ZvFdgBv+8/rkIU+46Tq4RTY+/hwTFN2aq48=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

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