SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b8f5d46d09bc707ccb554de41f8ddbf7ecaa9f20a815f8ddcc7729bf27018811' 
  AND token = '2BYhMAg08bzaqQguYQS/7Kk5q26wrVvYeoBK+eQOVdg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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