SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '83a5e89cb00c7a915442bcecf769e53b5d5261417270159539c0ef8950374ed3' 
  AND token = 'NdUq/nyY66JRQyeTi6PODlx8RFf4f573exb0tf0Eh8Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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