SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6d62f3beb91e4236c0cff1cadeaf6c08f3e215a13ec71cdb931c90a5d562a71f' 
  AND token = 'njpAYRIacdBpq5NlguG0uScFh5UJY3qbM3XFSfOGFwU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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