SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '99daa37694ce7bfe783ccda8a9cf5879c30f231ffa1ece496198178873309d71' 
  AND token = 'V0cAyblYQsP77VGV92cTKh+uAzC9Sg/efLleFe8OW5I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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