SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '21cef7ff188e9239afab90e8f0e733c84f7b09fd587f469c3fce0483006bd375' 
  AND token = 'w8Dy5OsDriOP3L9AAh8245hH+YcXPXU4kXbDin6Tp1o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

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