SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6e0fe05f10364e95920702abc084370f625a87ea07c9106794a7aa14cac880c1' 
  AND token = 'vGxFbaRhIlDjBWHjNjcDq0e8PlxTJfA95oCSr5tplSo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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