SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e84a3a7e492d4ca527dce5d286bbbd0bfac22c492ef02c4f94098bcc10074729' 
  AND token = 'UYxGXzGO3WxTL7bsmpk0q7DJxdDgduYSIpEUkhWoaK8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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