SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c2165cd4eb2f63841aed45073af4d382c7f7696d24768a91b76f54c40a040e52' 
  AND token = 'foOwodMxvIeRmv+fktsSQbzdB7gJktYvkinhgs9i458=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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