SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6097968cfaf4013a676701ece6562b624aa0803a61c7217530facfddf190c334' 
  AND token = 'VqoPmreqPApbeLkaYtKxY1PlJeWEkXjJkYUtxP5oPqc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

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