SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2c31976e41f25f40d9c9e3462a1c7c14eb0c28e944672c23cd1eae7a228462eb' 
  AND token = 'Scb+40Avc+Tv2WbiMSa7EmXlblpOXChjhcQk1gqzHXQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00014

JSON explain

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