SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3203c6cb6966dfbe4e7c083e78e7b5bff192d30c596fa74a044a84f44d49e792' 
  AND token = '9and4iS3wp3ZUfntd8WMoZv/KF5ksNJh/duUZLNo5GU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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