SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2c52f6beb5b1ce9dadc1397181403fcbe525d72461f705d73a4e7593e44e5f0b' 
  AND token = 'lpdqG6YaFmgAhDeBLo++/Yr+7Zj4zlthhpz2fzMR0lE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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