SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '04c3de8495468a06b3274ef44aea69285122ee123d7d702c3a86e59a97ee9def' 
  AND token = 'YgRIPI/BVDlrvpa6BKnjvfTcxGkOiNurTt8WOYbEDt4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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