SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '31e7f89bd7dcb573d21789b1e12d0a82fcf71f4f380957c26ea9d810c6c61411' 
  AND token = 'HnzyYydp/XkzuFObnIYDuOPnsNxYseHkcYPlxiVvitk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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