SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3926429c07eed0075d993d9e82e63d95afefab89fa264fb1b9b202dc66be5171' 
  AND token = 'nA4plts0kjpnb0tmxdzz7Q+CXM+vMvryX25eO+I33pQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

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