SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'aacb493f6d951cdd4e0bf512a5ab6fc8f57be156ddea85c701abbda8590990f7' 
  AND token = 'gKLmYRqB1lBavPV56+5yTTkGpF738CsvzpEZ6QsKbGQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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