SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '09d107c9bca6020c233a7cebb736eba3058c8b10408dd4d3d6b536e7131f89c2' 
  AND token = 'jax7+IzPT1e1BlgMWEjujxBYJKBB+RxlPL5lLm1qOls=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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