SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '866d498282de3b71f5e3a9b3513d395aceaa32c80ed7b8c005e8af7b1ff65ef9' 
  AND token = 'lrVKlgbUbeWslI9cYqGiUNQE+N1rq7H4VMnKwz/OItg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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