SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c727e24f65dbd8f5bfa221cded66cb8f863b95f8c966b96cbbf6ff8fcd4db98b' 
  AND token = 'v4Ba1jm33hOPgd+mNQGN8OwmWIqOUUgE9I5zlMgAME8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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