SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '95a55fb436b111bc64552c176dc22cbbbebced9169bd426e660965dee244b471' 
  AND token = 'C/buFuOKSMDwfDIwE8yXAz8PCx7Nsx6NaWL80SlvUjs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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