SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7b46ca6d750058efa34ddfd4ea3ac7b9969bca9610ef7c5f39dcadd460c9ceaa' 
  AND token = 'iqkGTUXidXB8bJt0W9Q/dsj7DdRGsDudaeqdAxYSibE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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