SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5b56471614008d88cc5db46cb2adcd43e5f3c2623a6e78856cb66507932cfca7' 
  AND token = 'vuo5fvrU6gnAoIuFt0ApX6QQQ5rcpWl0Uz9JhVnow7k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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