SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b6caaa68640a75d7eca44d8d2953657856941221086d6cfed5ac336312d2d45a' 
  AND token = 'oetI5O8icxVxFBqKU1IiBP+NdEVikCXYMYxCgk1HJ4U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00012

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