SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '589a782c6c52f36c4955392baf992e7c3a21222f207b7dbd905ce848173c45bb' 
  AND token = 'xdBOdck9FdGfPpguVVuM+GbGe9mTlZByOuNR/XiuxaY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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