SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2af79e31bb8a7e54c86d7aebfa973c860975ca1b2962775ca536fc9375eefb69' 
  AND token = 'rAjjIBGZQ3iudMrwVKChkF3W7LtuI+6UoEskZLdDTPA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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