SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e73b7764f0a6af8261024c7b0127492a6d7b47c969acb8aede1ac17e8802a897' 
  AND token = 'ZEsNP3IijdQ5mP9Zjzo2EEYkgCjM8zSEdJO/swvGL8I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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