SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6388b42e841c5f7803cd9805398db95f4547bbe807f780108d6904fd8e562be0' 
  AND token = 'SwS9l8QTPWOlzTcQbuckfljV6GvQgnJirAtEozHBf6I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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