SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '577d79b10e6b717c8a58ff5800f73fffe8822308c507193f648b297c313747df' 
  AND token = 'r4LJ13jRrJbQQtfPV4MywQHvh68uARe/6otUcPbMN7E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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