SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1d83d9b76c37bf5ac9c2376e648f38c2901b3145c8cff0ae54cccb496bbbd16f' 
  AND token = 'jMZqjVYPH2dSkTr8c1IgJXwrF+j0Kd6ltC/sQRdKttI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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