SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd447c6cbe422f5e7ccef45fb832b6c961527c56d1bb6708a5228b713d4ee8bb4' 
  AND token = 'iDpXINpBAvGgFffkcdAeK2gjQMz8BPA1Ej5+a4WnVKo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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