SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '02dfb68665a657f754ab85d74f59b82729d2620bad809ab03eb993975d9276c4' 
  AND token = 'LMhIEu7TteS2gjcf3pNOYHdhhP/bNeU/IGSlccWzM8I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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