SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ec8e0db4651cf397afe2f874ad496cfb6f4bdf29f057d101e32da98ff8568d9c' 
  AND token = 'V0GBnPgFZI8MQIGKlGjYBqhJm/4TMngHPRJXSvlM4QU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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