SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '261cbd2ab7e6ac830dd278ab4f0e077a4c378e9e743385cebbbaeb543f26fb17' 
  AND token = 'MqTozhGz3Vjo5nmiwdXTFlSeE4qYHhIOtJfLhViCK9g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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