SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ffba56e7141e73625a44faac08b68b158bf348101a8090276a901b613161dc8f' 
  AND token = 'pGJIFxjXRsvAioclW4g5gErW4tmmj5yx1NpymzxK7mM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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