SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fbefdbe78eb1b227d89ccbbaf2450983766c50cc6a69396c4c43b24d6051aef5' 
  AND token = 'qT+AffQbdKpsxFGhDoQ638ilRebr7jvKhl9kUzpLgUU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}