SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a792fe979a4fc53380636d5da12fde5c881884504b86723f12df6cfb5ec1231c' 
  AND token = 'RrOUl+7X8QmxT+RUcTwwxR/t+/pigw/cdQQZLAmbJNM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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