SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a923aac939139afea542f5e325e25184b623a5a2e11654ed82a778372bfbced9' 
  AND token = 'wlayW3NpQxd6PzKHt/Z73q6mf0LqEAmzxJemD1uEW2E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

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