SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '012c72809e32a668095ac25604152fed57cfd921c6a7665a4bf08797b7f92cf2' 
  AND token = 'AZpj65+nBA1hJpks5giULOhyw0O2LKlnlZtdNxTGsLM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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