SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '433224678636920dff299cc5afdf786b914d69bbc1ee4d268e4f6ac66399bb84' 
  AND token = 'NBNm3tx7/8VfRVVomTcuXhXqjTFb1rBMqDaWjd2QCFE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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