SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fe92e72a049c49eafa7baca312f18d5c77e8810a3d802483a40725962ce46b0a' 
  AND token = '1Fw2BIGh7YU+vOJGcMaqVJY4iDl/kc7P0a9ySYWjCRg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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