SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fb4b3bef87f065973d9cc2d77b0e2fdfec8c685f9f1a2421e4068a5ec0291fb2' 
  AND token = 'fzdWmd5ZJ5xDcxyfNpSfC/wUtf5o4HcwRxLFa80tTF4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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