SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b12a894a3f42564b86c14d4e85008316aec7badf7d40bf7464b5410cc58fc669' 
  AND token = 'VXl48dTqAHmTVOxU+1/N1HzVf5SxCn7Rb0BtldHDfz0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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