SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '98d6e4fe19c00fc768a460621ca72eb6529d1998af0a83f9d36c283103305552' 
  AND token = 'uHGoysakzVg4ZjrdgjCoQjnJKbyMOE8ZdS9sZ/DHC7A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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