SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'b47b6fdbf8f2f93da90d9b3e77c35f6da40da9e8c94a21b03aeac7e204ca386f' 
  AND token = 'XbVJBNb6R3rNWdMq9vxHPa7yfBpxS+W3fDAZaoOHgGQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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