SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5327bb7df222dc86dfced4afed63ca81072490ff371191330efaab22d09ff074' 
  AND token = '3Y3nFqhGUSQrhZFa4aCYsUlZz5ZQ6AgJodtoA2iLD1Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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