SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dd8e9dc2ced4e44a658b70a357bf625c435f811df35b0c8bce16055d28cee65b' 
  AND token = 'CQ2T5PnbBYOyRgsAnPng8c5risWCifmHYP58sInc678=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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