SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6cef995d005bff79c277ea624f214d0fc744f7ffd8bb58616b09bbe3a257b091' 
  AND token = 'DOYjr3FNMTSL/58QHBoMSsfRK8gjsgcKoZjcvbMtYO8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

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