SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9c177d818311669220a2554b385dde36ca5ec7dff13ad85237ca258b493b4c75' 
  AND token = 'gRxyHDZvsYuWYoJHSLzPuDHYZxRMwoAeMiK/c2oKa+g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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