SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '47410a91dda33c71320e1e5790c271b41f845456cac7fab750b05bdc5086bf23' 
  AND token = 'dDjyaqNfUTfY3zn1D9md55RsYHk7XRSOf/e4vSAuUQs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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