SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ddd6e953e17c5f15e7a22a41b594ef9ab9af9a8bb09e9beeb519cbffbccc38a3' 
  AND token = 'U4Y+sWgsXhcpEEHJUCZepjHvBraiDlDYa8ebC/fJP/c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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