SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '35a7cc98f8e020c8d8ba27e355f4296608f3d7e13e752dbb3f3af7a997a3b23d' 
  AND token = 'YBc9JTYi3anbhRG7/josWvrv0LIYA6vmrspj9lb0/O4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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