SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cdde243f7b956c1a04f9ab06f05e31ee9c56b309adf08107255d7e59842fd608' 
  AND token = 'SxhTGf10pu285l1hRUBtBjALkMJvhTkFhhfVrKCv1rk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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