SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '43def7301da25badc82c3a1c7b507032c37eccb4540bd99abc12001381855889' 
  AND token = 'QbUQfHEj9cjLrmlX19iEu/AxotVm5hUthO5kc3FkNQY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}