SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8eb45de64ea87d3b1c7c9227ffeca7ac3a2013b540ca9400cb951cb50b697525' 
  AND token = 'i+8sfRo8ZDpQ+XxZkDMeY1XWuQslLUnf4SHVRf6HN4Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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