SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4aae7ad5ae05934da881d25a317dd8cd52f00c3fe4f8fa472e80894f1ea45003' 
  AND token = '3JuMvCINBwmyDuOJFTKAYiiDgdZ0maKlnPAJ2Ie9be4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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