SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ad9ebe09704174da07980e6b78cea2220c214d7ec734f391c7092c07db47020a' 
  AND token = '3Hp3ZJ8+8Ux9QCPWZ0L0s5jkgSnfAlNxPfzuvM86wQ0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

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