SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd797be001a7548712d80cfe272bec148ea823cee32eafa20ebc9ad2f801071ac' 
  AND token = 'nRGqqrT3U4S+UEqf0FiWlYRT+7EFr+DjGp09pr2oZ8Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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