SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e0cc59c4aed4823027e6dc3986b69e777734908f4f6e255cb918c13f51822f91' 
  AND token = 'XrWmw7ktiSpFp9Gduw4rwHWNDmmmutTaPHZikSpkIZQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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