SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '87ba388ffcfc7b9bd50296e8c741e9de3db776ad5580a9f9d0b3467102196a3f' 
  AND token = 'ISpbVuPpVcjgcTL1ogQcwDbbWzAHJ3bFkLMDt/Frbd8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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