SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4f6b9665b0595af9b7d769498f75765a7138d7e33c1c9c0b622bb672c5184733' 
  AND token = 'FR7KQPwiqGUJKA8EPnbuiXYM+LqPzkGHhrEgBkkW4AA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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