SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'f78a53c3852a1fb51c629aacbc4ad642b98c085545c1c3e46ff35d7604110c4a' 
  AND token = '0QguoGZhtnQMnqGFqp7BGyUboTTblWOKxKzu3lNpeUY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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