SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '81fd5adf4e1087dc5528de97996c40d931a9ec9dee2a3ff637d7cc43601d06f7' 
  AND token = 'RkZ5NsCh2VAu8FML+1JNt7wOyk48BPs2GO26mYq0Zq8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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