SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '453f6b05245ae811d53148dc0af58f0c51bbd6974af481ac812abfb40a199e1b' 
  AND token = '6I7WLG0iREubooPbTWr45pOxSscOJIiCwsoK4i5S+bI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00014

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