SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd35f93187e8a70d33cbeb6fbf487e191df5284ada7b88e6d515639e296b8d47a' 
  AND token = '96DJWg1GjRTw/gKWVtcVcSWjxyJ+ihBYBs/Xj9xYmZc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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