SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ab6cb282081c1fd93b19a58ff302f7911dd6a65408c2d8ae154012fcd1fd734b' 
  AND token = '3gMVPXyDl7vx7RFA/JzOYwWfWhm3QKf/NtB+F1bTmYI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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