SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c9a309fbe9cbde740bb035f528db4efc8a3671ccc7f13ef93ca89c82cd09ca54' 
  AND token = '9MzKzqFb6eZ/D5lyTzkTVKwxorfrZ6l/prTjaSwZgGM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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