SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '407e552b78a64fa44ffa4d4fff24b8cfb4115593e05bd2d37820808a7e4047a9' 
  AND token = 'QzRa3sJJL8Vlr/qzGYiHKqibGChXHzZxIiQzXD4GeuQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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