SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4efbec4ba1578f79f58567365fc4a7cb385061282c6c3eb8f75ee96e410a6f83' 
  AND token = 'JM5xiO3KPoiOfpNjkgy2mhnO9nJKdBHmDqdbuTnxkyQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00013

JSON explain

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