SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '20fc2a99b24818afd50594e7e04568385dbe061d738b7f1a10f3f66aa6c3b19d' 
  AND token = 'DfEtGR/MHUiX4+PKLUe85+zXHe39qAmeGYN68btws5E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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