SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '39578ef4ee682031d0b23cc3e5f82402ffe3177295c19839f5bb94afc4817c64' 
  AND token = '7aGPnsHSGI0JZF4Ml/1FbOo8wpeE4giRMVPzvedKxv4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00059

JSON explain

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