SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'abe52c1c734228eb310e662f275a787bf19f5f156f719673c170264ddc8946a5' 
  AND token = 'eh2DgAugmY8qWFJsHmLIIXHe0XF5fpvZyM7/ij6dh4Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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