SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7af670c97e3cb1fedb45eced973e32d4bbc57813b9fed2b38ba2377ed2b08ba7' 
  AND token = 'cG/jPg0l7SmXO8dTK5hxwtmltefjXdNwYMfGuh6xAGk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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