SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '98a1fe461b0a03ee643a4cd915c926d9f4710db119bf749746d5bc16de1fb101' 
  AND token = 'DzHP05mMmShiUd97ZZrPG6CnkY/5yCdohyZHjaIBmNo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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