SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6f9952a83443d0cb12ac3e9d4e4fb14b9bf27036c44d05ea1433f51790ef9cfc' 
  AND token = 'ftwvoOkBFipKPwkmZtDZwzoE8jFXg9tK8OZBY1sve2M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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