SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4fc0e7e97b3ca5ee63e2a3e3f103a70c4cbc7b057bba232dbff4d74a4ce8b256' 
  AND token = 'kIGyLODAxbJu4a6fxwwhsxCwtFm9S25CfdO5NsHxwl0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}