SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fc690b15004bd85c06a966d7f53aad75f5f29f6575c8463db9fa992320c75bec' 
  AND token = 'F7zBbaq0cM627Ty4ucSW6ZhW0OZhT0BwLvzh8cMeRYw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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