SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6d2fab193823b93ee1b05c26c2f6df7a9460413a023131447008c0fa699e5587' 
  AND token = 'HGR0MrkYV1kGzMnOaeWccnEYoNseCNzfuhwOjQ+bJGA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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