SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '991736d37b8decc714264b3859159adf102c193de43845f545f9467ab3eedadf' 
  AND token = 'AjOv1Tam26D6kvwWDLqnY2dZgM6A5H7O3xGlnVdUBqw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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