SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '37c668f369da55911384ea025e4872b37cbd5bb8dc3df4b6aaf8651fe25f608c' 
  AND token = 'GZeDLzLAYw2f8V0RPj5qwVRhu4O//WeO7EJqqh3qjB0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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